diff --git a/paddle/capi/Arguments.cpp b/paddle/capi/Arguments.cpp
index baabd44cc0c63caea6838ada9ea94e2b71876ea1..8d00bda3cb90cda9950533fff86c7c2f54b0448e 100644
--- a/paddle/capi/Arguments.cpp
+++ b/paddle/capi/Arguments.cpp
@@ -87,7 +87,6 @@ int PDArgsSetIds(PD_Arguments args, uint64_t ID, PD_IVector ids) {
 int PDArgsSetSequenceStartPos(PD_Arguments args,
                               uint64_t ID,
                               PD_IVector seqPos) {
-  //! TODO(lizhao): Complete this method.
   if (args == nullptr || seqPos == nullptr) return kPD_NULLPTR;
   auto iv = paddle::capi::cast<paddle::capi::CIVector>(seqPos);
   if (iv->vec == nullptr) return kPD_NULLPTR;
@@ -101,13 +100,12 @@ int PDArgsSetSequenceStartPos(PD_Arguments args,
 int PDArgsSetSubSequenceStartPos(PD_Arguments args,
                                  uint64_t ID,
                                  PD_IVector subSeqPos) {
-  //! TODO(lizhao): Complete this method.
   if (args == nullptr || subSeqPos == nullptr) return kPD_NULLPTR;
   auto iv = paddle::capi::cast<paddle::capi::CIVector>(subSeqPos);
   if (iv->vec == nullptr) return kPD_NULLPTR;
   auto a = castArg(args);
   if (ID >= a->args.size()) return kPD_OUT_OF_RANGE;
-  a->args[ID].sequenceStartPositions =
+  a->args[ID].subSequenceStartPositions =
       std::make_shared<paddle::ICpuGpuVector>(iv->vec);
   return kPD_NO_ERROR;
 }
@@ -115,26 +113,24 @@ int PDArgsSetSubSequenceStartPos(PD_Arguments args,
 int PDArgsGetSequenceStartPos(PD_Arguments args,
                               uint64_t ID,
                               PD_IVector seqPos) {
-  //! TODO(lizhao): Complete this method.
   if (args == nullptr || seqPos == nullptr) return kPD_NULLPTR;
   auto iv = castIVec(seqPos);
   auto a = castArg(args);
   if (ID >= a->args.size()) return kPD_OUT_OF_RANGE;
-  std::make_shared<paddle::ICpuGpuVector>(iv->vec) =
-      a->args[ID].sequenceStartPositions;
+  paddle::Argument& arg = a->args[ID];
+  iv->vec = arg.sequenceStartPositions->getMutableVector(false);
   return kPD_NO_ERROR;
 }
 
 int PDArgsGetSubSequenceStartPos(PD_Arguments args,
                                  uint64_t ID,
                                  PD_IVector subSeqPos) {
-  //! TODO(lizhao): Complete this method.
   if (args == nullptr || subSeqPos == nullptr) return kPD_NULLPTR;
   auto iv = castIVec(subSeqPos);
   auto a = castArg(args);
   if (ID >= a->args.size()) return kPD_OUT_OF_RANGE;
-  std::make_shared<paddle::ICpuGpuVector>(iv->vec) =
-      a->args[ID].sequenceStartPositions;
+  paddle::Argument& arg = a->args[ID];
+  iv->vec = arg.subSequenceStartPositions->getMutableVector(false);
   return kPD_NO_ERROR;
 }
 }
diff --git a/paddle/capi/Vector.cpp b/paddle/capi/Vector.cpp
index 38a5fbc00a8bebd524816d8a39364d7ca0c196c8..af2192551370f4d6ec3e0affc2cf8fa5b3ac2021 100644
--- a/paddle/capi/Vector.cpp
+++ b/paddle/capi/Vector.cpp
@@ -27,7 +27,6 @@ int PDIVecCreateNone(PD_IVector* ivec) {
 }
 
 int PDIVectorCreate(PD_IVector* ivec, int* array, uint64_t size, bool copy) {
-  //! TODO(lizhao): Complete this method.
   if (ivec == nullptr) return kPD_NULLPTR;
   auto ptr = new paddle::capi::CIVector();
   if (copy) {
@@ -55,7 +54,6 @@ int PDIVectorGet(PD_IVector ivec, int** buffer) {
 }
 
 int PDIVectorResize(PD_IVector ivec, uint64_t size) {
-  //! TODO(lizhao): Complete this method.
   if (ivec == nullptr) return kPD_NULLPTR;
   auto v = cast<paddle::capi::CIVector>(ivec);
   if (v->vec == nullptr) return kPD_NULLPTR;
@@ -64,7 +62,6 @@ int PDIVectorResize(PD_IVector ivec, uint64_t size) {
 }
 
 int PDIVectorGetSize(PD_IVector ivec, uint64_t* size) {
-  //! TODO(lizhao): Complete this method.
   if (ivec == nullptr) return kPD_NULLPTR;
   auto v = cast<paddle::capi::CIVector>(ivec);
   if (v->vec == nullptr) return kPD_NULLPTR;
diff --git a/paddle/capi/tests/test_Arguments.cpp b/paddle/capi/tests/test_Arguments.cpp
index 1186d2921ba463b9b7e4156e9985e458d52484b0..9357f3a58468e9d7ffc38fc595895c5e5568a09a 100644
--- a/paddle/capi/tests/test_Arguments.cpp
+++ b/paddle/capi/tests/test_Arguments.cpp
@@ -89,7 +89,8 @@ TEST(CAPIArguments, ids) {
   ASSERT_EQ(kPD_NO_ERROR, PDArgsDestroy(args));
 }
 
-TEST(CAPIArguments, Sequence) {
+template <typename T1, typename T2>
+void testSequenceHelper(T1 setter, T2 getter) {
   PD_Arguments args;
   ASSERT_EQ(kPD_NO_ERROR, PDArgsCreateNone(&args));
   ASSERT_EQ(kPD_NO_ERROR, PDArgsResize(args, 1));
@@ -97,12 +98,27 @@ TEST(CAPIArguments, Sequence) {
   PD_IVector ivec;
   int array[3] = {1, 2, 3};
   ASSERT_EQ(kPD_NO_ERROR, PDIVectorCreate(&ivec, array, 3, true));
-  ASSERT_EQ(kPD_NO_ERROR, PDArgsSetSequenceStartPos(args, 0, ivec));
+  ASSERT_EQ(kPD_NO_ERROR, setter(args, 0, ivec));
 
   PD_IVector val;
   ASSERT_EQ(kPD_NO_ERROR, PDIVecCreateNone(&val));
-  ASSERT_EQ(kPD_NO_ERROR, PDArgsGetSequenceStartPos(args, 0, val));
+  ASSERT_EQ(kPD_NO_ERROR, getter(args, 0, val));
+  uint64_t size;
+  ASSERT_EQ(kPD_NO_ERROR, PDIVectorGetSize(val, &size));
+
+  int* rawBuf;
+  ASSERT_EQ(kPD_NO_ERROR, PDIVectorGet(val, &rawBuf));
+  for (size_t i = 0; i < size; ++i) {
+    ASSERT_EQ(array[i], rawBuf[i]);
+  }
+
   ASSERT_EQ(kPD_NO_ERROR, PDIVecDestroy(ivec));
   ASSERT_EQ(kPD_NO_ERROR, PDIVecDestroy(val));
   ASSERT_EQ(kPD_NO_ERROR, PDArgsDestroy(args));
 }
+
+TEST(CAPIArguments, Sequence) {
+  testSequenceHelper(PDArgsSetSequenceStartPos, PDArgsGetSequenceStartPos);
+  testSequenceHelper(PDArgsSetSubSequenceStartPos,
+                     PDArgsGetSubSequenceStartPos);
+}