diff --git a/paddle/fluid/inference/tensorrt/engine.cc b/paddle/fluid/inference/tensorrt/engine.cc
index 03f5a751511adba7b508db9944c30d17866bad2d..22be877493272cd393538fd4f04184e77d38e2db 100644
--- a/paddle/fluid/inference/tensorrt/engine.cc
+++ b/paddle/fluid/inference/tensorrt/engine.cc
@@ -186,6 +186,14 @@ void TensorRTEngine::FreezeNetwork() {
           Vec2TRT_Dims(optim_input_shape_[input.first], input.first, true));
     }
     infer_builder_config_->addOptimizationProfile(optim_profile_);
+    infer_builder_config_->setMaxWorkspaceSize(max_workspace_);
+    if (enable_int8) {
+      // Due to a bug of TRT, we must set precision BuilderFlag to kFP16 before
+      // kINT8 here to perform INT8 inference.
+      infer_builder_config_->setFlag(nvinfer1::BuilderFlag::kFP16);
+      infer_builder_config_->setFlag(nvinfer1::BuilderFlag::kINT8);
+      infer_builder_config_->setFlag(nvinfer1::BuilderFlag::kSTRICT_TYPES);
+    }
     if (WithFp16()) {
       infer_builder_config_->setFlag(nvinfer1::BuilderFlag::kFP16);
       if (disable_trt_plugin_fp16()) {
diff --git a/paddle/fluid/inference/tensorrt/op_teller.cc b/paddle/fluid/inference/tensorrt/op_teller.cc
index f5d22b982de2b41474d97565a44dedc67c8a85d7..e8cbb9431cb3c79ed6c6269f96c256fd50afb121 100644
--- a/paddle/fluid/inference/tensorrt/op_teller.cc
+++ b/paddle/fluid/inference/tensorrt/op_teller.cc
@@ -51,6 +51,7 @@ struct SimpleOpTypeSetTeller : public Teller {
                                                   "relu",
                                                   "depthwise_conv2d",
                                                   "softmax",
+                                                  "sigmoid",
                                                   "batch_norm",
                                                   "elementwise_add",
                                                   "leaky_relu",
diff --git a/paddle/fluid/inference/tests/api/CMakeLists.txt b/paddle/fluid/inference/tests/api/CMakeLists.txt
index 2bd30bc05179e2881c4ecb321d76d5506233cc0e..07af5c152b1cd42d1034ed9c5a1d8d8bc3782827 100644
--- a/paddle/fluid/inference/tests/api/CMakeLists.txt
+++ b/paddle/fluid/inference/tests/api/CMakeLists.txt
@@ -431,9 +431,9 @@ if(WITH_GPU AND TENSORRT_FOUND)
             EXTRA_DEPS ${INFERENCE_EXTRA_DEPS} paddle_fluid_c
             ARGS --infer_model=${TRT_MODEL_INSTALL_DIR}/trt_inference_test_models)
      
-    set(TRT_MODEL_QUANT_RESNET_DIR "${INFERENCE_DEMO_INSTALL_DIR}/quant_small_model")
+    set(TRT_MODEL_QUANT_RESNET_DIR "${INFERENCE_DEMO_INSTALL_DIR}/small_quant_model")
     if (NOT EXISTS ${TRT_MODEL_QUANT_RESNET_DIR})
-        inference_download_and_uncompress(${INFERENCE_DEMO_INSTALL_DIR} ${INFERENCE_URL}/tensorrt_test "quant_small_model.tar.gz")
+        inference_download_and_uncompress(${INFERENCE_DEMO_INSTALL_DIR} ${INFERENCE_URL}/tensorrt_test "small_quant_model.tgz")
     endif()
     inference_analysis_test(trt_quant_int8_test SRCS trt_quant_int8_test.cc
             EXTRA_DEPS ${INFERENCE_EXTRA_DEPS}
diff --git a/paddle/fluid/inference/tests/api/trt_quant_int8_test.cc b/paddle/fluid/inference/tests/api/trt_quant_int8_test.cc
index ca5cdbbcb26c81d028d87a7ec186c73d6e2b7fde..6adf3cf743b0e3c303b28c1e4cdc3b4be376bf32 100644
--- a/paddle/fluid/inference/tests/api/trt_quant_int8_test.cc
+++ b/paddle/fluid/inference/tests/api/trt_quant_int8_test.cc
@@ -25,12 +25,20 @@ namespace inference {
 TEST(quant_int8, resnet50) {
   std::string model_dir = FLAGS_infer_model;
   AnalysisConfig config;
-  config.EnableUseGpu(100, 0);
+  config.EnableUseGpu(1000, 0);
   config.SetModel(model_dir);
   config.SwitchUseFeedFetchOps(false);
   config.EnableTensorRtEngine(1 << 30, 1, 1, AnalysisConfig::Precision::kInt8,
                               false, false);
+  std::map<std::string, std::vector<int>> min_input_shape = {
+      {"image", {1, 1, 3, 3}}};
+  std::map<std::string, std::vector<int>> max_input_shape = {
+      {"image", {1, 1, 10, 10}}};
+  std::map<std::string, std::vector<int>> opt_input_shape = {
+      {"image", {1, 1, 3, 3}}};
 
+  config.SetTRTDynamicShapeInfo(min_input_shape, max_input_shape,
+                                opt_input_shape);
   auto predictor = CreatePaddlePredictor(config);
   auto input_names = predictor->GetInputNames();
   int channels = 1;