diff --git a/modules/planning/optimizer/st_graph/st_graph_boundary.cc b/modules/planning/optimizer/st_graph/st_graph_boundary.cc
index 448dd9255fbbf62ace912eb7b0817d3ff4b4f4c2..2ff4364914dfc483dfc4b5a0fdccee35a0ee499a 100644
--- a/modules/planning/optimizer/st_graph/st_graph_boundary.cc
+++ b/modules/planning/optimizer/st_graph/st_graph_boundary.cc
@@ -79,9 +79,9 @@ bool StGraphBoundary::IsPointInBoundary(const STPoint& st_point) const {
   return IsPointIn(st_point);
 }
 
-Vec2d StGraphBoundary::point(const uint32_t index) const {
+STPoint StGraphBoundary::point(const uint32_t index) const {
   CHECK_LT(index, points_.size()) << "Index[" << index << "] is out of range.";
-  return points_[index];
+  return STPoint(points_[index].y(), points_[index].x());
 }
 
 const std::vector<Vec2d>& StGraphBoundary::points() const { return points_; }
diff --git a/modules/planning/optimizer/st_graph/st_graph_boundary.h b/modules/planning/optimizer/st_graph/st_graph_boundary.h
index 58f78f2976b9e9d98d8456f54d6e2f9fd5ee9d3c..f21801022695c77a8b356e0c10c7a6b173ce9b9b 100644
--- a/modules/planning/optimizer/st_graph/st_graph_boundary.h
+++ b/modules/planning/optimizer/st_graph/st_graph_boundary.h
@@ -60,7 +60,7 @@ class StGraphBoundary : public common::math::Polygon2d {
   bool IsPointInBoundary(const StGraphPoint& st_graph_point) const;
   bool IsPointInBoundary(const STPoint& st_point) const;
 
-  common::math::Vec2d point(const uint32_t index) const;
+  STPoint point(const uint32_t index) const;
   const std::vector<common::math::Vec2d>& points() const;
 
   BoundaryType boundary_type() const;