diff --git a/modules/planning/tasks/BUILD b/modules/planning/tasks/BUILD
index 6153ac4b1f7ccf292ed033247b0fe7893999d3e2..77898f11d5c7b1bb0342951c7a0bf697e9090eb4 100644
--- a/modules/planning/tasks/BUILD
+++ b/modules/planning/tasks/BUILD
@@ -55,7 +55,7 @@ cc_library(
         "//modules/planning/common:speed_limit",
         "//modules/planning/common/path:path_data",
         "//modules/planning/common/speed:speed_data",
-        "//modules/planning/tasks/st_graph:st_graph_boundary",
+        "//modules/planning/tasks/st_graph:st_boundary",
         "//modules/planning/tasks/st_graph:st_graph_point",
         "@eigen//:eigen",
     ],
diff --git a/modules/planning/tasks/dp_st_speed/BUILD b/modules/planning/tasks/dp_st_speed/BUILD
index 638a677b94ba8887dedf681c3f2b02b92cde01f7..663a233ad902434f91e37cb51131e22267225f51 100644
--- a/modules/planning/tasks/dp_st_speed/BUILD
+++ b/modules/planning/tasks/dp_st_speed/BUILD
@@ -14,7 +14,7 @@ cc_library(
         "//modules/common/proto:pnc_point_proto",
         "//modules/planning/common:frame",
         "//modules/planning/math:double",
-        "//modules/planning/tasks/st_graph:st_graph_boundary",
+        "//modules/planning/tasks/st_graph:st_boundary",
         "//modules/planning/proto:dp_st_speed_config_proto",
     ],
 )
diff --git a/modules/planning/tasks/dp_st_speed/dp_st_cost.cc b/modules/planning/tasks/dp_st_speed/dp_st_cost.cc
index 97f4189f98941081cba029f2681a3c58aeb0a06c..f277e0deef9fb7105550d570b82ddf68135b4260 100644
--- a/modules/planning/tasks/dp_st_speed/dp_st_cost.cc
+++ b/modules/planning/tasks/dp_st_speed/dp_st_cost.cc
@@ -38,9 +38,9 @@ DpStCost::DpStCost(const DpStSpeedConfig& dp_st_speed_config)
 // TODO(all): normalize cost with time
 double DpStCost::GetObstacleCost(
     const STPoint& point,
-    const std::vector<StGraphBoundary>& st_graph_boundaries) const {
+    const std::vector<StBoundary>& st_graph_boundaries) const {
   double total_cost = 0.0;
-  for (const StGraphBoundary& boundary : st_graph_boundaries) {
+  for (const StBoundary& boundary : st_graph_boundaries) {
     if (point.s() < 0 || boundary.IsPointInBoundary(point)) {
       total_cost = std::numeric_limits<double>::infinity();
       break;
diff --git a/modules/planning/tasks/dp_st_speed/dp_st_cost.h b/modules/planning/tasks/dp_st_speed/dp_st_cost.h
index 847ba31ae0dad5148b2ffefa0b4b8cd5578e6075..708eb99b5870293acc440d54a956774caa96dd30 100644
--- a/modules/planning/tasks/dp_st_speed/dp_st_cost.h
+++ b/modules/planning/tasks/dp_st_speed/dp_st_cost.h
@@ -27,7 +27,7 @@
 #include "modules/planning/proto/dp_st_speed_config.pb.h"
 
 #include "modules/planning/common/speed/st_point.h"
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 
 namespace apollo {
 namespace planning {
@@ -38,7 +38,7 @@ class DpStCost {
 
   double GetObstacleCost(
       const STPoint& point,
-      const std::vector<StGraphBoundary>& st_graph_boundaries) const;
+      const std::vector<StBoundary>& st_graph_boundaries) const;
 
   double GetReferenceCost(const STPoint& point,
                           const STPoint& reference_point) const;
diff --git a/modules/planning/tasks/dp_st_speed/dp_st_graph.cc b/modules/planning/tasks/dp_st_speed/dp_st_graph.cc
index a6b00edc1b1656bc2fb78f1e7f2420d38888f933..b72028258728e2fe7b8d9b8fcd273cea3d0f4eec 100644
--- a/modules/planning/tasks/dp_st_speed/dp_st_graph.cc
+++ b/modules/planning/tasks/dp_st_speed/dp_st_graph.cc
@@ -42,7 +42,7 @@ using Vec2d = apollo::common::math::Vec2d;
 
 namespace {
 
-bool CheckOverlapOnDpStGraph(const std::vector<StGraphBoundary> boundaries,
+bool CheckOverlapOnDpStGraph(const std::vector<StBoundary> boundaries,
                              const StGraphPoint& p1, const StGraphPoint& p2) {
   for (const auto& boundary : boundaries) {
     common::math::LineSegment2d seg(p1.point(), p2.point());
@@ -135,7 +135,7 @@ Status DpStGraph::InitCostTable() {
 }
 
 void DpStGraph::CalculatePointwiseCost(
-    const std::vector<StGraphBoundary>& boundaries) {
+    const std::vector<StBoundary>& boundaries) {
   // TODO(all): extract reference line from decision first
   std::vector<STPoint> reference_points;
   double curr_t = 0.0;
@@ -533,7 +533,7 @@ bool DpStGraph::CreateFollowDecision(
 }
 
 bool DpStGraph::CreateYieldDecision(
-    const StGraphBoundary& boundary,
+    const StBoundary& boundary,
     ObjectDecisionType* const yield_decision) const {
   DCHECK_NOTNULL(yield_decision);
 
@@ -561,7 +561,7 @@ bool DpStGraph::CreateYieldDecision(
 }
 
 bool DpStGraph::CreateOvertakeDecision(
-    const PathObstacle& path_obstacle, const StGraphBoundary& boundary,
+    const PathObstacle& path_obstacle, const StBoundary& boundary,
     ObjectDecisionType* const overtake_decision) const {
   DCHECK_NOTNULL(overtake_decision);
 
@@ -631,7 +631,7 @@ double DpStGraph::CalculateEdgeCostForThirdCol(const uint32_t curr_row,
          dp_st_cost_.GetJerkCostByThreePoints(init_speed, first, second, third);
 }
 
-bool DpStGraph::CheckIsFollowByT(const StGraphBoundary& boundary) const {
+bool DpStGraph::CheckIsFollowByT(const StBoundary& boundary) const {
   DCHECK_EQ(boundary.points().size(), 4);
 
   if (boundary.BottomLeftPoint().s() > boundary.BottomRightPoint().s()) {
diff --git a/modules/planning/tasks/dp_st_speed/dp_st_graph.h b/modules/planning/tasks/dp_st_speed/dp_st_graph.h
index d913b790fea02481dca887ab51238975d149e263..058d8e9ac4d04c370dab60c8e33285a1c13b2840 100644
--- a/modules/planning/tasks/dp_st_speed/dp_st_graph.h
+++ b/modules/planning/tasks/dp_st_speed/dp_st_graph.h
@@ -50,7 +50,7 @@ class DpStGraph {
  private:
   apollo::common::Status InitCostTable();
 
-  void CalculatePointwiseCost(const std::vector<StGraphBoundary>& boundaries);
+  void CalculatePointwiseCost(const std::vector<StBoundary>& boundaries);
 
   apollo::common::Status RetrieveSpeedProfile(
       SpeedData* const speed_data) const;
@@ -76,12 +76,12 @@ class DpStGraph {
 
   /**
    * @brief check if the ADC should follow an obstacle by examing the
-   *StGraphBoundary of the obstacle.
+   *StBoundary of the obstacle.
    * @param boundary The boundary of the obstacle.
    * @return true if the ADC believe it should follow the obstacle, and
    *         false otherwise.
    **/
-  bool CheckIsFollowByT(const StGraphBoundary& boundary) const;
+  bool CheckIsFollowByT(const StBoundary& boundary) const;
 
   /**
    * @brief create follow decision based on the boundary
@@ -97,7 +97,7 @@ class DpStGraph {
    * @return true if the yield decision is created successfully, and
    *         false otherwise.
    **/
-  bool CreateYieldDecision(const StGraphBoundary& boundary,
+  bool CreateYieldDecision(const StBoundary& boundary,
                            ObjectDecisionType* const yield_decision) const;
 
   /**
@@ -106,7 +106,7 @@ class DpStGraph {
    *         false otherwise.
    **/
   bool CreateOvertakeDecision(
-      const PathObstacle& path_obstacle, const StGraphBoundary& boundary,
+      const PathObstacle& path_obstacle, const StBoundary& boundary,
       ObjectDecisionType* const overtake_decision) const;
 
   void GetRowRange(const uint32_t curr_row, const uint32_t curr_col,
diff --git a/modules/planning/tasks/dp_st_speed/dp_st_speed_optimizer.cc b/modules/planning/tasks/dp_st_speed/dp_st_speed_optimizer.cc
index 9b9e6824e82e9c13df2aefd95a1e88b586886ccb..da055f8946c0fb2787ac2af9f5bbc75b74e70b76 100644
--- a/modules/planning/tasks/dp_st_speed/dp_st_speed_optimizer.cc
+++ b/modules/planning/tasks/dp_st_speed/dp_st_speed_optimizer.cc
@@ -71,7 +71,7 @@ Status DpStSpeedOptimizer::Process(const PathData& path_data,
                                    dp_st_speed_config_.total_time());
 
   // step 1 get boundaries
-  std::vector<StGraphBoundary> boundaries;
+  std::vector<StBoundary> boundaries;
   if (boundary_mapper.GetGraphBoundary(*path_decision, &boundaries).code() ==
       ErrorCode::PLANNING_ERROR) {
     const std::string msg =
diff --git a/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.cc b/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.cc
index 56035fe618cdec0263310e4269bb29ec8725bde7..edbed6817430b393e149bce33f026e265710f484 100644
--- a/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.cc
+++ b/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.cc
@@ -125,7 +125,7 @@ Status QpSplineStGraph::Search(const StGraphData& st_graph_data,
 
 Status QpSplineStGraph::ApplyConstraint(
     const common::TrajectoryPoint& init_point, const SpeedLimit& speed_limit,
-    const std::vector<StGraphBoundary>& boundaries) {
+    const std::vector<StBoundary>& boundaries) {
   Spline1dConstraint* constraint =
       spline_generator_->mutable_spline_constraint();
   // position, velocity, acceleration
@@ -223,7 +223,7 @@ Status QpSplineStGraph::ApplyConstraint(
 }
 
 Status QpSplineStGraph::ApplyKernel(
-    const std::vector<StGraphBoundary>& boundaries,
+    const std::vector<StBoundary>& boundaries,
     const SpeedLimit& speed_limit) {
   Spline1dKernel* spline_kernel = spline_generator_->mutable_spline_kernel();
 
@@ -297,7 +297,7 @@ Status QpSplineStGraph::AddCruiseReferenceLineKernel(
 
 Status QpSplineStGraph::AddFollowReferenceLineKernel(
     const std::vector<double>& evaluate_t,
-    const std::vector<StGraphBoundary>& boundaries, const double weight) {
+    const std::vector<StBoundary>& boundaries, const double weight) {
   auto* spline_kernel = spline_generator_->mutable_spline_kernel();
   std::vector<double> ref_s;
   std::vector<double> filtered_evaluate_t;
@@ -305,7 +305,7 @@ Status QpSplineStGraph::AddFollowReferenceLineKernel(
     double s_min = std::numeric_limits<double>::infinity();
     bool success = false;
     for (const auto& boundary : boundaries) {
-      if (boundary.boundary_type() != StGraphBoundary::BoundaryType::FOLLOW) {
+      if (boundary.boundary_type() != StBoundary::BoundaryType::FOLLOW) {
         continue;
       }
       double s_upper = 0.0;
@@ -336,12 +336,12 @@ Status QpSplineStGraph::AddFollowReferenceLineKernel(
 }
 
 Status QpSplineStGraph::GetSConstraintByTime(
-    const std::vector<StGraphBoundary>& boundaries, const double time,
+    const std::vector<StBoundary>& boundaries, const double time,
     const double total_path_s, double* const s_upper_bound,
     double* const s_lower_bound) const {
   *s_upper_bound = total_path_s;
 
-  for (const StGraphBoundary& boundary : boundaries) {
+  for (const StBoundary& boundary : boundaries) {
     double s_upper = 0.0;
     double s_lower = 0.0;
 
@@ -349,13 +349,13 @@ Status QpSplineStGraph::GetSConstraintByTime(
       continue;
     }
 
-    if (boundary.boundary_type() == StGraphBoundary::BoundaryType::STOP ||
-        boundary.boundary_type() == StGraphBoundary::BoundaryType::FOLLOW ||
-        boundary.boundary_type() == StGraphBoundary::BoundaryType::YIELD) {
+    if (boundary.boundary_type() == StBoundary::BoundaryType::STOP ||
+        boundary.boundary_type() == StBoundary::BoundaryType::FOLLOW ||
+        boundary.boundary_type() == StBoundary::BoundaryType::YIELD) {
       *s_upper_bound = std::fmin(*s_upper_bound, s_upper);
     } else {
       DCHECK(boundary.boundary_type() ==
-             StGraphBoundary::BoundaryType::OVERTAKE);
+             StBoundary::BoundaryType::OVERTAKE);
       *s_lower_bound = std::fmax(*s_lower_bound, s_lower);
     }
   }
diff --git a/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.h b/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.h
index 0e5948085b9396fff8ad44a6bde35c36959e3d73..0c028e9a8270cd90d3b039d72da126fce4d57162 100644
--- a/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.h
+++ b/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_graph.h
@@ -34,7 +34,7 @@
 #include "modules/planning/common/planning_util.h"
 #include "modules/planning/common/speed/speed_data.h"
 #include "modules/planning/math/smoothing_spline/spline_1d_generator.h"
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 #include "modules/planning/tasks/st_graph/st_graph_data.h"
 
 namespace apollo {
@@ -54,10 +54,10 @@ class QpSplineStGraph {
   // apply st graph constraint
   common::Status ApplyConstraint(
       const common::TrajectoryPoint& init_point, const SpeedLimit& speed_limit,
-      const std::vector<StGraphBoundary>& boundaries);
+      const std::vector<StBoundary>& boundaries);
 
   // apply objective function
-  common::Status ApplyKernel(const std::vector<StGraphBoundary>& boundaries,
+  common::Status ApplyKernel(const std::vector<StBoundary>& boundaries,
                              const SpeedLimit& speed_limit);
 
   // solve
@@ -65,7 +65,7 @@ class QpSplineStGraph {
 
   // extract upper lower bound for constraint;
   common::Status GetSConstraintByTime(
-      const std::vector<StGraphBoundary>& boundaries, const double time,
+      const std::vector<StBoundary>& boundaries, const double time,
       const double total_path_s, double* const s_upper_bound,
       double* const s_lower_bound) const;
 
@@ -77,7 +77,7 @@ class QpSplineStGraph {
 
   common::Status AddFollowReferenceLineKernel(
       const std::vector<double>& evaluate_t,
-      const std::vector<StGraphBoundary>& boundaries, const double weight);
+      const std::vector<StBoundary>& boundaries, const double weight);
 
   common::Status EstimateSpeedUpperBound(
       const common::TrajectoryPoint& init_point, const SpeedLimit& speed_limit,
diff --git a/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_speed_optimizer.cc b/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_speed_optimizer.cc
index a3108dfb4a0cbf48661becb57676bb715196f2dc..fbaa627ce745b89c101fbf46d8b9fee1612bb611 100644
--- a/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_speed_optimizer.cc
+++ b/modules/planning/tasks/qp_spline_st_speed/qp_spline_st_speed_optimizer.cc
@@ -75,7 +75,7 @@ Status QpSplineStSpeedOptimizer::Process(const PathData& path_data,
     DCHECK(path_obstacle->HasLongitudinalDecision());
   }
   // step 1 get boundaries
-  std::vector<StGraphBoundary> boundaries;
+  std::vector<StBoundary> boundaries;
   if (boundary_mapper.GetGraphBoundary(*path_decision, &boundaries).code() ==
       ErrorCode::PLANNING_ERROR) {
     return Status(ErrorCode::PLANNING_ERROR,
@@ -84,7 +84,7 @@ Status QpSplineStSpeedOptimizer::Process(const PathData& path_data,
 
   for (const auto& boundary : boundaries) {
     ADEBUG << "QPST mapped boundary: " << boundary.DebugString() << std::endl;
-    DCHECK(boundary.boundary_type() != StGraphBoundary::BoundaryType::UNKNOWN);
+    DCHECK(boundary.boundary_type() != StBoundary::BoundaryType::UNKNOWN);
   }
 
   SpeedLimit speed_limits;
diff --git a/modules/planning/tasks/speed_optimizer.cc b/modules/planning/tasks/speed_optimizer.cc
index 3f27eab3314ad0f849d09291a606c86bacd64bb5..1399b58e4f429e7319c89585ac41056b15c70ca8 100644
--- a/modules/planning/tasks/speed_optimizer.cc
+++ b/modules/planning/tasks/speed_optimizer.cc
@@ -49,7 +49,7 @@ void SpeedOptimizer::RecordDebugInfo(const SpeedData& speed_data) {
 }
 
 void SpeedOptimizer::RecordSTGraphDebug(
-    const std::vector<StGraphBoundary>& boundaries,
+    const std::vector<StBoundary>& boundaries,
     const SpeedLimit& speed_limits, const SpeedData& speed_data) {
   if (!FLAGS_enable_record_debug) {
     ADEBUG << "Skip record debug info";
diff --git a/modules/planning/tasks/speed_optimizer.h b/modules/planning/tasks/speed_optimizer.h
index 02f3f5e9b8b1ad37ad6cc7250951ccdc8d79c203..f4b342e04b0e9d63cde87206f734d4333177f0b0 100644
--- a/modules/planning/tasks/speed_optimizer.h
+++ b/modules/planning/tasks/speed_optimizer.h
@@ -27,7 +27,7 @@
 #include "modules/common/status/status.h"
 #include "modules/planning/common/speed/speed_data.h"
 #include "modules/planning/common/speed_limit.h"
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 #include "modules/planning/tasks/task.h"
 
 namespace apollo {
@@ -46,7 +46,7 @@ class SpeedOptimizer : public Task {
       const ReferenceLine& reference_line, PathDecision* const path_decision,
       SpeedData* const speed_data) = 0;
 
-  void RecordSTGraphDebug(const std::vector<StGraphBoundary>& boundaries,
+  void RecordSTGraphDebug(const std::vector<StBoundary>& boundaries,
                           const SpeedLimit& speed_limits,
                           const SpeedData& speed_data);
 
diff --git a/modules/planning/tasks/st_graph/BUILD b/modules/planning/tasks/st_graph/BUILD
index e1f8f067879c9c6aa9ea64ac6ffec033db213803..161d7c0c441c162061761a190fdd32de39424e8c 100644
--- a/modules/planning/tasks/st_graph/BUILD
+++ b/modules/planning/tasks/st_graph/BUILD
@@ -17,12 +17,12 @@ cc_library(
 )
 
 cc_library(
-    name = "st_graph_boundary",
+    name = "st_boundary",
     srcs = [
-        "st_graph_boundary.cc",
+        "st_boundary.cc",
     ],
     hdrs = [
-        "st_graph_boundary.h",
+        "st_boundary.h",
     ],
     deps = [
         ":st_graph_point",
@@ -41,7 +41,7 @@ cc_library(
         "st_graph_data.h",
     ],
     deps = [
-        ":st_graph_boundary",
+        ":st_boundary",
         "//modules/planning/common:planning_gflags",
         "//modules/planning/common:speed_limit",
     ],
@@ -56,7 +56,7 @@ cc_library(
         "st_boundary_mapper.h",
     ],
     deps = [
-        ":st_graph_boundary",
+        ":st_boundary",
         "//modules/common/configs:vehicle_config_helper",
         "//modules/common/configs/proto:vehicle_config_proto",
         "//modules/common/proto:pnc_point_proto",
@@ -98,13 +98,13 @@ cc_test(
 )
 
 cc_test(
-    name = "st_graph_boundary_test",
+    name = "st_boundary_test",
     size = "small",
     srcs = [
-        "st_graph_boundary_test.cc",
+        "st_boundary_test.cc",
     ],
     deps = [
-        ":st_graph_boundary",
+        ":st_boundary",
         "//modules/common:log",
         "//modules/common/time",
         "//modules/common/util",
@@ -119,7 +119,7 @@ cc_test(
         "st_graph_data_test.cc",
     ],
     deps = [
-        ":st_graph_boundary",
+        ":st_boundary",
         ":st_graph_data",
         "//modules/common:log",
         "//modules/common/time",
diff --git a/modules/planning/tasks/st_graph/st_graph_boundary.cc b/modules/planning/tasks/st_graph/st_boundary.cc
similarity index 64%
rename from modules/planning/tasks/st_graph/st_graph_boundary.cc
rename to modules/planning/tasks/st_graph/st_boundary.cc
index 632b144c85593026fbba359bab962f046aa2877e..2b524856e72c8b4ab61f5a628546b701d4cfa855 100644
--- a/modules/planning/tasks/st_graph/st_graph_boundary.cc
+++ b/modules/planning/tasks/st_graph/st_boundary.cc
@@ -15,10 +15,10 @@
  *****************************************************************************/
 
 /**
-  * @file: obstacle_st_boundary.cc
+  * @file
   **/
 
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 
 #include <algorithm>
 
@@ -29,10 +29,10 @@ namespace planning {
 
 using Vec2d = common::math::Vec2d;
 
-StGraphBoundary::StGraphBoundary(const std::vector<STPoint>& points)
+StBoundary::StBoundary(const std::vector<STPoint>& points)
     : Polygon2d(std::vector<Vec2d>(points.begin(), points.end())) {
   CHECK_EQ(points.size(), 4)
-      << "StGraphBoundary must have exactly four points. Input points size: "
+      << "StBoundary must have exactly four points. Input points size: "
       << points.size();
   for (const auto& point : points) {
     min_s_ = std::fmin(min_s_, point.s());
@@ -42,11 +42,10 @@ StGraphBoundary::StGraphBoundary(const std::vector<STPoint>& points)
   }
 }
 
-StGraphBoundary::StGraphBoundary(
-    const std::vector<::apollo::common::math::Vec2d>& points)
+StBoundary::StBoundary(const std::vector<::apollo::common::math::Vec2d>& points)
     : Polygon2d(points) {
   CHECK_EQ(points.size(), 4)
-      << "StGraphBoundary must have exactly four points. Input points size: "
+      << "StBoundary must have exactly four points. Input points size: "
       << points.size();
   for (const auto& point : points) {
     min_s_ = std::fmin(min_s_, point.y());
@@ -56,57 +55,55 @@ StGraphBoundary::StGraphBoundary(
   }
 }
 
-bool StGraphBoundary::IsPointInBoundary(
-    const StGraphPoint& st_graph_point) const {
+bool StBoundary::IsPointInBoundary(const StGraphPoint& st_graph_point) const {
   return IsPointInBoundary(st_graph_point.point());
 }
 
-bool StGraphBoundary::IsPointInBoundary(const STPoint& st_point) const {
+bool StBoundary::IsPointInBoundary(const STPoint& st_point) const {
   return IsPointIn(st_point);
 }
 
-STPoint StGraphBoundary::BottomLeftPoint() const {
-  DCHECK(!points_.empty()) << "StGraphBoundary has zero points.";
+STPoint StBoundary::BottomLeftPoint() const {
+  DCHECK(!points_.empty()) << "StBoundary has zero points.";
   return STPoint(points_.at(0).y(), points_.at(0).x());
 }
 
-STPoint StGraphBoundary::BottomRightPoint() const {
-  DCHECK(!points_.empty()) << "StGraphBoundary has zero points.";
+STPoint StBoundary::BottomRightPoint() const {
+  DCHECK(!points_.empty()) << "StBoundary has zero points.";
   return STPoint(points_.at(1).y(), points_.at(1).x());
 }
 
-STPoint StGraphBoundary::TopRightPoint() const {
-  DCHECK(!points_.empty()) << "StGraphBoundary has zero points.";
+STPoint StBoundary::TopRightPoint() const {
+  DCHECK(!points_.empty()) << "StBoundary has zero points.";
   return STPoint(points_.at(2).y(), points_.at(2).x());
 }
 
-STPoint StGraphBoundary::TopLeftPoint() const {
-  DCHECK(!points_.empty()) << "StGraphBoundary has zero points.";
+STPoint StBoundary::TopLeftPoint() const {
+  DCHECK(!points_.empty()) << "StBoundary has zero points.";
   return STPoint(points_.at(3).y(), points_.at(3).x());
 }
 
-StGraphBoundary::BoundaryType StGraphBoundary::boundary_type() const {
+StBoundary::BoundaryType StBoundary::boundary_type() const {
   return boundary_type_;
 }
-void StGraphBoundary::SetBoundaryType(const BoundaryType& boundary_type) {
+void StBoundary::SetBoundaryType(const BoundaryType& boundary_type) {
   boundary_type_ = boundary_type;
 }
 
-const std::string& StGraphBoundary::id() const { return id_; }
+const std::string& StBoundary::id() const { return id_; }
 
-void StGraphBoundary::SetId(const std::string& id) { id_ = id; }
+void StBoundary::SetId(const std::string& id) { id_ = id; }
 
-double StGraphBoundary::characteristic_length() const {
+double StBoundary::characteristic_length() const {
   return characteristic_length_;
 }
 
-void StGraphBoundary::SetCharacteristicLength(
-    const double characteristic_length) {
+void StBoundary::SetCharacteristicLength(const double characteristic_length) {
   characteristic_length_ = characteristic_length;
 }
 
-bool StGraphBoundary::GetUnblockSRange(const double curr_time, double* s_upper,
-                                       double* s_lower) const {
+bool StBoundary::GetUnblockSRange(const double curr_time, double* s_upper,
+                                  double* s_lower) const {
   const common::math::LineSegment2d segment = {Vec2d(curr_time, 0.0),
                                                Vec2d(curr_time, s_high_limit_)};
   *s_upper = s_high_limit_;
@@ -135,8 +132,8 @@ bool StGraphBoundary::GetUnblockSRange(const double curr_time, double* s_upper,
   return true;
 }
 
-bool StGraphBoundary::GetBoundarySRange(const double curr_time, double* s_upper,
-                                        double* s_lower) const {
+bool StBoundary::GetBoundarySRange(const double curr_time, double* s_upper,
+                                   double* s_lower) const {
   const common::math::LineSegment2d segment = {Vec2d(curr_time, 0.0),
                                                Vec2d(curr_time, s_high_limit_)};
   *s_upper = s_high_limit_;
@@ -154,10 +151,10 @@ bool StGraphBoundary::GetBoundarySRange(const double curr_time, double* s_upper,
   return true;
 }
 
-double StGraphBoundary::min_s() const { return min_s_; }
-double StGraphBoundary::min_t() const { return min_t_; }
-double StGraphBoundary::max_s() const { return max_s_; }
-double StGraphBoundary::max_t() const { return max_t_; }
+double StBoundary::min_s() const { return min_s_; }
+double StBoundary::min_t() const { return min_t_; }
+double StBoundary::max_s() const { return max_s_; }
+double StBoundary::max_t() const { return max_t_; }
 
 }  // namespace planning
 }  // namespace apollo
diff --git a/modules/planning/tasks/st_graph/st_graph_boundary.h b/modules/planning/tasks/st_graph/st_boundary.h
similarity index 90%
rename from modules/planning/tasks/st_graph/st_graph_boundary.h
rename to modules/planning/tasks/st_graph/st_boundary.h
index 74ec1fe1bdd6ca2a8a840f4f501abe03749f4c70..6e9e756376c3eda027b7f987a2d5ac652fbd81c0 100644
--- a/modules/planning/tasks/st_graph/st_graph_boundary.h
+++ b/modules/planning/tasks/st_graph/st_boundary.h
@@ -15,7 +15,7 @@
  *****************************************************************************/
 
 /**
- *   @file: st_graph_boundary.h
+ *   @file
  **/
 
 #ifndef MODULES_PLANNING_TASKS_ST_GRAPH_ST_GRAPH_BOUNDARY_H_
@@ -34,16 +34,16 @@
 namespace apollo {
 namespace planning {
 
-class StGraphBoundary : public common::math::Polygon2d {
+class StBoundary : public common::math::Polygon2d {
  public:
-  StGraphBoundary() = default;
+  StBoundary() = default;
 
   // boundary points go counter clockwise.
-  explicit StGraphBoundary(const std::vector<STPoint>& points);
+  explicit StBoundary(const std::vector<STPoint>& points);
 
   // boundary points go counter clockwise.
-  explicit StGraphBoundary(const std::vector<common::math::Vec2d>& points);
-  ~StGraphBoundary() = default;
+  explicit StBoundary(const std::vector<common::math::Vec2d>& points);
+  ~StBoundary() = default;
 
   // if you need to add boundary type, make sure you modify
   // GetUnblockSRange accordingly.
diff --git a/modules/planning/tasks/st_graph/st_boundary_mapper.cc b/modules/planning/tasks/st_graph/st_boundary_mapper.cc
index 1a53559d6cc024d39698af9a2de2770af436aae6..bda730644a987b8200e943870702964f9d95998e 100644
--- a/modules/planning/tasks/st_graph/st_boundary_mapper.cc
+++ b/modules/planning/tasks/st_graph/st_boundary_mapper.cc
@@ -79,7 +79,7 @@ StBoundaryMapper::StBoundaryMapper(const StBoundaryConfig& config,
 
 Status StBoundaryMapper::GetGraphBoundary(
     const PathDecision& path_decision,
-    std::vector<StGraphBoundary>* const st_graph_boundaries) const {
+    std::vector<StBoundary>* const st_graph_boundaries) const {
   const auto& path_obstacles = path_decision.path_obstacles();
   if (st_graph_boundaries == nullptr) {
     const std::string msg = "st_graph_boundaries is NULL.";
@@ -110,7 +110,7 @@ Status StBoundaryMapper::GetGraphBoundary(
 
   for (const auto* path_obstacle : path_obstacles.Items()) {
     if (!path_obstacle->HasLongitudinalDecision()) {
-      StGraphBoundary boundary;
+      StBoundary boundary;
       const auto ret = MapWithoutDecision(*path_obstacle, &boundary);
       if (!ret.ok()) {
         std::string msg = common::util::StrCat(
@@ -123,7 +123,7 @@ Status StBoundaryMapper::GetGraphBoundary(
     }
     const auto& decision = path_obstacle->LongitudinalDecision();
     if (decision.has_follow()) {
-      StGraphBoundary follow_boundary;
+      StBoundary follow_boundary;
       const auto ret =
           MapFollowDecision(*path_obstacle, decision, &follow_boundary);
       if (!ret.ok()) {
@@ -152,7 +152,7 @@ Status StBoundaryMapper::GetGraphBoundary(
         stop_decision = decision;
       }
     } else if (decision.has_overtake() || decision.has_yield()) {
-      StGraphBoundary boundary;
+      StBoundary boundary;
       const auto ret =
           MapWithPredictionTrajectory(*path_obstacle, decision, &boundary);
       if (!ret.ok()) {
@@ -168,7 +168,7 @@ Status StBoundaryMapper::GetGraphBoundary(
   }
 
   if (stop_obstacle) {
-    StGraphBoundary stop_boundary;
+    StBoundary stop_boundary;
     bool success =
         MapStopDecision(*stop_obstacle, stop_decision, &stop_boundary);
     if (!success) {
@@ -178,16 +178,16 @@ Status StBoundaryMapper::GetGraphBoundary(
     }
     AppendBoundary(stop_boundary, st_graph_boundaries);
   }
-  for (const auto& st_graph_boundary : *st_graph_boundaries) {
-    DCHECK_EQ(st_graph_boundary.points().size(), 4);
-    DCHECK_NE(st_graph_boundary.id().length(), 0);
+  for (const auto& st_boundary : *st_graph_boundaries) {
+    DCHECK_EQ(st_boundary.points().size(), 4);
+    DCHECK_NE(st_boundary.id().length(), 0);
   }
   return Status::OK();
 }
 
 bool StBoundaryMapper::MapStopDecision(const PathObstacle& stop_obstacle,
                                        const ObjectDecisionType& stop_decision,
-                                       StGraphBoundary* const boundary) const {
+                                       StBoundary* const boundary) const {
   CHECK_NOTNULL(boundary);
   DCHECK(stop_decision.has_stop()) << "Must have stop decision";
 
@@ -222,15 +222,15 @@ bool StBoundaryMapper::MapStopDecision(const PathObstacle& stop_obstacle,
                                planning_time_);
   boundary_points.emplace_back(s_max, 0.0);
 
-  *boundary = StGraphBoundary(boundary_points);
-  boundary->SetBoundaryType(StGraphBoundary::BoundaryType::STOP);
+  *boundary = StBoundary(boundary_points);
+  boundary->SetBoundaryType(StBoundary::BoundaryType::STOP);
   boundary->SetCharacteristicLength(st_boundary_config_.boundary_buffer());
   boundary->SetId(stop_obstacle.Id());
   return true;
 }
 
 Status StBoundaryMapper::MapWithoutDecision(
-    const PathObstacle& path_obstacle, StGraphBoundary* const boundary) const {
+    const PathObstacle& path_obstacle, StBoundary* const boundary) const {
   std::vector<STPoint> lower_points;
   std::vector<STPoint> upper_points;
 
@@ -257,7 +257,7 @@ Status StBoundaryMapper::MapWithoutDecision(
       AWARN << "lower/upper points are reversed.";
     }
 
-    *boundary = StGraphBoundary(boundary_points);
+    *boundary = StBoundary(boundary_points);
     boundary->SetId(path_obstacle.Obstacle()->Id());
   }
   return Status::OK();
@@ -344,7 +344,7 @@ bool StBoundaryMapper::GetOverlapBoundaryPoints(
 
 Status StBoundaryMapper::MapWithPredictionTrajectory(
     const PathObstacle& path_obstacle, const ObjectDecisionType& obj_decision,
-    StGraphBoundary* const boundary) const {
+    StBoundary* const boundary) const {
   DCHECK_NOTNULL(boundary);
   DCHECK(obj_decision.has_follow() || obj_decision.has_yield() ||
          obj_decision.has_overtake())
@@ -387,8 +387,8 @@ Status StBoundaryMapper::MapWithPredictionTrajectory(
     }
 
     // change boundary according to obj_decision.
-    StGraphBoundary::BoundaryType b_type =
-        StGraphBoundary::BoundaryType::UNKNOWN;
+    StBoundary::BoundaryType b_type =
+        StBoundary::BoundaryType::UNKNOWN;
     double characteristic_length = 0.0;
     constexpr double kBoundaryEpsilon = 1e-3;
     if (obj_decision.has_follow()) {
@@ -404,7 +404,7 @@ Status StBoundaryMapper::MapWithPredictionTrajectory(
       boundary_points.at(0).set_s(boundary_points.at(0).s());
       boundary_points.at(1).set_s(boundary_points.at(1).s());
       boundary_points.at(3).set_t(-1.0);
-      b_type = StGraphBoundary::BoundaryType::FOLLOW;
+      b_type = StBoundary::BoundaryType::FOLLOW;
     } else if (obj_decision.has_yield()) {
       const double dis = std::fabs(obj_decision.yield().distance_s());
       characteristic_length = dis;
@@ -422,7 +422,7 @@ Status StBoundaryMapper::MapWithPredictionTrajectory(
         boundary_points.at(1).set_s(boundary_points.at(1).s() - dis);
       }
       boundary_points.at(3).set_t(-kBoundaryEpsilon);
-      b_type = StGraphBoundary::BoundaryType::YIELD;
+      b_type = StBoundary::BoundaryType::YIELD;
 
     } else if (obj_decision.has_overtake()) {
       const double dis = std::fabs(obj_decision.overtake().distance_s());
@@ -433,12 +433,12 @@ Status StBoundaryMapper::MapWithPredictionTrajectory(
 
       const double time_buffer = obj_decision.overtake().time_buffer();
       boundary_points.at(3).set_t(boundary_points.at(3).t() - time_buffer);
-      b_type = StGraphBoundary::BoundaryType::OVERTAKE;
+      b_type = StBoundary::BoundaryType::OVERTAKE;
     } else {
       DCHECK(false) << "Obj decision should be either yield or overtake: "
                     << obj_decision.DebugString();
     }
-    *boundary = StGraphBoundary(boundary_points);
+    *boundary = StBoundary(boundary_points);
     boundary->SetBoundaryType(b_type);
     boundary->SetId(path_obstacle.Obstacle()->Id());
     boundary->SetCharacteristicLength(characteristic_length);
@@ -448,7 +448,7 @@ Status StBoundaryMapper::MapWithPredictionTrajectory(
 
 Status StBoundaryMapper::MapFollowDecision(
     const PathObstacle& path_obstacle, const ObjectDecisionType& obj_decision,
-    StGraphBoundary* const boundary) const {
+    StBoundary* const boundary) const {
   DCHECK_NOTNULL(boundary);
   DCHECK(obj_decision.has_follow())
       << "Map obstacle without prediction trajectory is ONLY supported when "
@@ -513,7 +513,7 @@ Status StBoundaryMapper::MapFollowDecision(
   boundary_points.emplace_back(s_max_upper, planning_time_);
   boundary_points.emplace_back(s_min_upper, 0.0);
 
-  *boundary = StGraphBoundary(boundary_points);
+  *boundary = StBoundary(boundary_points);
 
   const double characteristic_length =
       std::fabs(obj_decision.follow().distance_s()) +
@@ -521,7 +521,7 @@ Status StBoundaryMapper::MapFollowDecision(
 
   boundary->SetCharacteristicLength(characteristic_length);
   boundary->SetId(obstacle->Id());
-  boundary->SetBoundaryType(StGraphBoundary::BoundaryType::FOLLOW);
+  boundary->SetBoundaryType(StBoundary::BoundaryType::FOLLOW);
 
   return Status::OK();
 }
@@ -574,8 +574,8 @@ Status StBoundaryMapper::GetSpeedLimits(
 }
 
 void StBoundaryMapper::AppendBoundary(
-    const StGraphBoundary& boundary,
-    std::vector<StGraphBoundary>* st_graph_boundaries) const {
+    const StBoundary& boundary,
+    std::vector<StBoundary>* st_graph_boundaries) const {
   if (Double::Compare(boundary.area(), 0.0) <= 0) {
     return;
   }
diff --git a/modules/planning/tasks/st_graph/st_boundary_mapper.h b/modules/planning/tasks/st_graph/st_boundary_mapper.h
index d9f61efe6e287466177ac4f3a25becab48367c64..68e55c2c3d6559d4697a168f4bc08f9e3a8fd328 100644
--- a/modules/planning/tasks/st_graph/st_boundary_mapper.h
+++ b/modules/planning/tasks/st_graph/st_boundary_mapper.h
@@ -30,7 +30,7 @@
 #include "modules/planning/common/path/path_data.h"
 #include "modules/planning/common/path_decision.h"
 #include "modules/planning/common/speed_limit.h"
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 #include "modules/planning/reference_line/reference_line.h"
 
 namespace apollo {
@@ -45,7 +45,7 @@ class StBoundaryMapper {
 
   apollo::common::Status GetGraphBoundary(
       const PathDecision& path_decision,
-      std::vector<StGraphBoundary>* const boundary) const;
+      std::vector<StBoundary>* const boundary) const;
 
   virtual apollo::common::Status GetSpeedLimits(
       SpeedLimit* const speed_limit_data) const;
@@ -62,22 +62,22 @@ class StBoundaryMapper {
       std::vector<STPoint>* lower_points) const;
 
   apollo::common::Status MapWithoutDecision(
-      const PathObstacle& path_obstacle, StGraphBoundary* const boundary) const;
+      const PathObstacle& path_obstacle, StBoundary* const boundary) const;
 
   bool MapStopDecision(const PathObstacle& stop_obstacle,
                        const ObjectDecisionType& stop_decision,
-                       StGraphBoundary* const boundary) const;
+                       StBoundary* const boundary) const;
 
   apollo::common::Status MapWithPredictionTrajectory(
       const PathObstacle& path_obstacle, const ObjectDecisionType& obj_decision,
-      StGraphBoundary* const boundary) const;
+      StBoundary* const boundary) const;
 
   apollo::common::Status MapFollowDecision(
       const PathObstacle& obstacle, const ObjectDecisionType& obj_decision,
-      StGraphBoundary* const boundary) const;
+      StBoundary* const boundary) const;
 
-  void AppendBoundary(const StGraphBoundary& boundary,
-                      std::vector<StGraphBoundary>* st_graph_boundaries) const;
+  void AppendBoundary(const StBoundary& boundary,
+                      std::vector<StBoundary>* st_graph_boundaries) const;
 
  private:
   StBoundaryConfig st_boundary_config_;
diff --git a/modules/planning/tasks/st_graph/st_graph_boundary_test.cc b/modules/planning/tasks/st_graph/st_boundary_test.cc
similarity index 85%
rename from modules/planning/tasks/st_graph/st_graph_boundary_test.cc
rename to modules/planning/tasks/st_graph/st_boundary_test.cc
index 72a76f3166764d21980c8624e4f9f735c54f6dea..6fc7f2a01b15b560ff3ebf350f57cd9e1e76114e 100644
--- a/modules/planning/tasks/st_graph/st_graph_boundary_test.cc
+++ b/modules/planning/tasks/st_graph/st_boundary_test.cc
@@ -14,7 +14,7 @@
  * limitations under the License.
  *****************************************************************************/
 
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 
 #include <algorithm>
 #include <cmath>
@@ -27,30 +27,30 @@
 namespace apollo {
 namespace planning {
 
-TEST(StGraphBoundaryTest, basic_test) {
+TEST(StBoundaryTest, basic_test) {
   std::vector<STPoint> st_points;
   st_points.emplace_back(0.0, 0.0);
   st_points.emplace_back(0.0, 10.0);
   st_points.emplace_back(5.0, 10.0);
   st_points.emplace_back(5.0, 0.0);
 
-  StGraphBoundary boundary(st_points);
+  StBoundary boundary(st_points);
   EXPECT_EQ(boundary.id(), "");
-  EXPECT_EQ(boundary.boundary_type(), StGraphBoundary::BoundaryType::UNKNOWN);
+  EXPECT_EQ(boundary.boundary_type(), StBoundary::BoundaryType::UNKNOWN);
   EXPECT_FLOAT_EQ(0.0, boundary.min_s());
   EXPECT_FLOAT_EQ(5.0, boundary.max_s());
   EXPECT_FLOAT_EQ(0.0, boundary.min_t());
   EXPECT_FLOAT_EQ(10.0, boundary.max_t());
 }
 
-TEST(StGraphBoundaryTest, boundary_range) {
+TEST(StBoundaryTest, boundary_range) {
   std::vector<STPoint> st_points;
   st_points.emplace_back(1.0, 0.0);
   st_points.emplace_back(1.0, 10.0);
   st_points.emplace_back(5.0, 10.0);
   st_points.emplace_back(5.0, 0.0);
-  StGraphBoundary boundary(st_points);
-  boundary.SetBoundaryType(StGraphBoundary::BoundaryType::YIELD);
+  StBoundary boundary(st_points);
+  boundary.SetBoundaryType(StBoundary::BoundaryType::YIELD);
   double t = -10.0;
   const double dt = 0.01;
   while (t < 10.0) {
diff --git a/modules/planning/tasks/st_graph/st_graph_data.cc b/modules/planning/tasks/st_graph/st_graph_data.cc
index 59d91680c85526cb6bb11b301ae4b10a5fffce87..9ac7adf8476d33d51c68cac734c8fff680e35c2a 100644
--- a/modules/planning/tasks/st_graph/st_graph_data.cc
+++ b/modules/planning/tasks/st_graph/st_graph_data.cc
@@ -26,7 +26,7 @@ namespace planning {
 using apollo::common::TrajectoryPoint;
 
 StGraphData::StGraphData(
-    const std::vector<StGraphBoundary>& st_graph_boundaries,
+    const std::vector<StBoundary>& st_graph_boundaries,
     const TrajectoryPoint& init_point, const SpeedLimit& speed_limit,
     const double path_data_length)
     : st_graph_boundaries_(st_graph_boundaries),
@@ -34,7 +34,7 @@ StGraphData::StGraphData(
       speed_limit_(speed_limit),
       path_data_length_(path_data_length) {}
 
-const std::vector<StGraphBoundary>& StGraphData::st_graph_boundaries() const {
+const std::vector<StBoundary>& StGraphData::st_graph_boundaries() const {
   return st_graph_boundaries_;
 }
 
diff --git a/modules/planning/tasks/st_graph/st_graph_data.h b/modules/planning/tasks/st_graph/st_graph_data.h
index a6023c1c0ad9bd06288ff653f51f6055a44b58d7..29c641a7153759a3b9f187fefe596b97a882b27b 100644
--- a/modules/planning/tasks/st_graph/st_graph_data.h
+++ b/modules/planning/tasks/st_graph/st_graph_data.h
@@ -27,7 +27,7 @@
 #include "modules/common/proto/pnc_point.pb.h"
 
 #include "modules/planning/common/speed_limit.h"
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 
 namespace apollo {
 namespace planning {
@@ -36,11 +36,11 @@ class StGraphData {
  public:
   StGraphData() = default;
 
-  StGraphData(const std::vector<StGraphBoundary>& st_graph_boundaries,
+  StGraphData(const std::vector<StBoundary>& st_graph_boundaries,
               const apollo::common::TrajectoryPoint& init_point,
               const SpeedLimit& speed_limit, const double path_data_length);
 
-  const std::vector<StGraphBoundary>& st_graph_boundaries() const;
+  const std::vector<StBoundary>& st_graph_boundaries() const;
 
   const apollo::common::TrajectoryPoint& init_point() const;
 
@@ -49,7 +49,7 @@ class StGraphData {
   double path_data_length() const;
 
  private:
-  std::vector<StGraphBoundary> st_graph_boundaries_;
+  std::vector<StBoundary> st_graph_boundaries_;
   apollo::common::TrajectoryPoint init_point_;
 
   SpeedLimit speed_limit_;
diff --git a/modules/planning/tasks/st_graph/st_graph_data_test.cc b/modules/planning/tasks/st_graph/st_graph_data_test.cc
index e34d36bb8612be53dfe354d8808f6bffe520b2fb..2cc994c774e4c8bc177f38a12478270e7af038aa 100644
--- a/modules/planning/tasks/st_graph/st_graph_data_test.cc
+++ b/modules/planning/tasks/st_graph/st_graph_data_test.cc
@@ -23,7 +23,7 @@
 #include "gtest/gtest.h"
 
 #include "modules/common/log.h"
-#include "modules/planning/tasks/st_graph/st_graph_boundary.h"
+#include "modules/planning/tasks/st_graph/st_boundary.h"
 
 namespace apollo {
 namespace planning {
@@ -43,8 +43,8 @@ TEST(StGraphDataTest, basic_test) {
   EXPECT_DOUBLE_EQ(st_graph_data.init_point().relative_time(), 0.0);
   EXPECT_DOUBLE_EQ(st_graph_data.path_data_length(), 0.0);
 
-  std::vector<StGraphBoundary> boundary_vec;
-  boundary_vec.push_back(StGraphBoundary());
+  std::vector<StBoundary> boundary_vec;
+  boundary_vec.push_back(StBoundary());
   apollo::common::TrajectoryPoint traj_point;
   traj_point.mutable_path_point()->set_x(1.1);
   traj_point.mutable_path_point()->set_y(2.1);