diff --git a/paddle/function/Function.h b/paddle/function/Function.h
index 561cd5fdc793650901948a0f52829148fcab95f0..9ad00c6f370cf64e9cc26f16e62c4d2ddb284003 100644
--- a/paddle/function/Function.h
+++ b/paddle/function/Function.h
@@ -20,6 +20,7 @@ limitations under the License. */
 #include "paddle/math/Matrix.h"
 #include "paddle/utils/Any.h"
 #include "paddle/utils/ClassRegistrar.h"
+#include "paddle/utils/Error.h"
 
 namespace paddle {
 
@@ -30,12 +31,30 @@ namespace paddle {
 class FuncConfig {
 public:
   template <typename T>
-  T get(const std::string& key) const {
-    return any_cast<T>(valueMap_[key]);
+  T get(const std::string& key, Error* err = nullptr) const {
+    try {
+      return any_cast<T>(valueMap_.at(key));
+    } catch (std::exception& e) {  // could be cast or out of range exception.
+      if (err) {
+        *err = Error(e.what());
+      } else {
+        LOG(FATAL) << "Cannot get key " << key << "with error " << e.what();
+      }
+      return T();
+    }
   }
 
   template <typename T>
-  FuncConfig& set(const std::string& key, T v) {
+  FuncConfig& set(const std::string& key, T v, Error* err = nullptr) {
+    auto it = valueMap_.find(key);
+    if (it != valueMap_.end()) {  // already contains key.
+      if (err) {
+        *err = Error("Key %s is already set in FuncConfig", key.c_str());
+      } else {
+        LOG(FATAL) << "Key " << key << " is already set in FuncConfig.";
+      }
+      return *this;
+    }
     valueMap_[key] = any(v);
     return *this;
   }
diff --git a/paddle/function/PadOp.cpp b/paddle/function/PadOp.cpp
index f1a0d2a1a96f24ddff8cd120681a8bc8cddaf40a..adba7c92ece505eecc74edce6b393cf27fa10ccc 100644
--- a/paddle/function/PadOp.cpp
+++ b/paddle/function/PadOp.cpp
@@ -25,9 +25,9 @@ void Pad<DEVICE_TYPE_CPU>(real* outputs,
                           const int inH,
                           const int inW,
                           const PadConf& pad) {
-  int cstart = pad.channelStart, cend = pad.channelEnd;
-  int hstart = pad.heightStart, hend = pad.heightEnd;
-  int wstart = pad.widthStart, wend = pad.widthEnd;
+  int cstart = pad.channel[0], cend = pad.channel[1];
+  int hstart = pad.height[0], hend = pad.height[1];
+  int wstart = pad.width[0], wend = pad.width[1];
   int outC = inC + cstart + cend;
   int outH = inH + hstart + hend;
   int outW = inW + wstart + wend;
@@ -51,9 +51,9 @@ void PadGrad<DEVICE_TYPE_CPU>(real* inGrad,
                               const int inH,
                               const int inW,
                               const PadConf& pad) {
-  int cstart = pad.channelStart, cend = pad.channelEnd;
-  int hstart = pad.heightStart, hend = pad.heightEnd;
-  int wstart = pad.widthStart, wend = pad.widthEnd;
+  int cstart = pad.channel[0], cend = pad.channel[1];
+  int hstart = pad.height[0], hend = pad.height[1];
+  int wstart = pad.width[0], wend = pad.width[1];
   int outC = inC + cstart + cend;
   int outH = inH + hstart + hend;
   int outW = inW + wstart + wend;
@@ -71,6 +71,12 @@ void PadGrad<DEVICE_TYPE_CPU>(real* inGrad,
   }
 }
 
+static inline PadConf castToPadConf(const FuncConfig& conf) {
+  return {conf.get<std::vector<uint32_t>>("channel"),
+          conf.get<std::vector<uint32_t>>("height"),
+          conf.get<std::vector<uint32_t>>("width")};
+}
+
 /**
  * \brief Padding zeros to input according to the specify dimension.
  *        The struct pad_ contains the padding size in each dimension.
@@ -127,14 +133,7 @@ void PadGrad<DEVICE_TYPE_CPU>(real* inGrad,
 template <DeviceType Device>
 class PadFunc : public FunctionBase {
 public:
-  void init(const FuncConfig& config) override {
-    pad_.channelStart = config.get<int>("cstart");
-    pad_.channelEnd = config.get<int>("cend");
-    pad_.heightStart = config.get<int>("hstart");
-    pad_.heightEnd = config.get<int>("hend");
-    pad_.widthStart = config.get<int>("wstart");
-    pad_.widthEnd = config.get<int>("wend");
-  }
+  void init(const FuncConfig& config) override { pad_ = castToPadConf(config); }
 
   void calc(const BufferArgs& inputs, const BufferArgs& outputs) override {
     CHECK_EQ(1UL, inputs.size());
@@ -175,14 +174,7 @@ private:
 template <DeviceType Device>
 class PadGradFunc : public FunctionBase {
 public:
-  void init(const FuncConfig& config) override {
-    pad_.channelStart = config.get<int>("cstart");
-    pad_.channelEnd = config.get<int>("cend");
-    pad_.heightStart = config.get<int>("hstart");
-    pad_.heightEnd = config.get<int>("hend");
-    pad_.widthStart = config.get<int>("wstart");
-    pad_.widthEnd = config.get<int>("wend");
-  }
+  void init(const FuncConfig& config) override { pad_ = castToPadConf(config); }
 
   void calc(const BufferArgs& inputs, const BufferArgs& outputs) override {
     CHECK_EQ(1UL, inputs.size());
diff --git a/paddle/function/PadOp.h b/paddle/function/PadOp.h
index 7b5c730a6a0fa57833e63beba085cb17054ae2f5..0e226ec7370b9897ebdc697ee528b90a37e4ec56 100644
--- a/paddle/function/PadOp.h
+++ b/paddle/function/PadOp.h
@@ -19,18 +19,12 @@ limitations under the License. */
 namespace paddle {
 
 struct PadConf {
-  /// how many values to add before the data along channel dimension.
-  int channelStart;
-  /// how many values to add after the data along channel dimension.
-  int channelEnd;
-  /// how many values to add before the data along height dimension.
-  int heightStart;
-  /// how many values to add after the data along height dimension.
-  int heightEnd;
-  /// how many values to add before the data along width dimension.
-  int widthStart;
-  /// how many values to add after the data along width dimension.
-  int widthEnd;
+  /// how many values to add before/after the data along channel dimension.
+  std::vector<uint32_t> channel;
+  /// how many values to add before/after the data along height dimension.
+  std::vector<uint32_t> height;
+  /// how many values to add before/after the data along width dimension.
+  std::vector<uint32_t> width;
 };
 
 /**
diff --git a/paddle/gserver/layers/PadLayer.cpp b/paddle/gserver/layers/PadLayer.cpp
index bb618c09f9777785d93995fa7140dd4a5383cd1b..a5ed7e057aea8f065ee752f8c0f0d2d9bdddfc8b 100644
--- a/paddle/gserver/layers/PadLayer.cpp
+++ b/paddle/gserver/layers/PadLayer.cpp
@@ -36,12 +36,9 @@ bool PadLayer::init(const LayerMap& layerMap,
   CHECK_EQ(2, pad_conf.pad_c_size());
   CHECK_EQ(2, pad_conf.pad_h_size());
   CHECK_EQ(2, pad_conf.pad_w_size());
-  padc_.push_back(pad_conf.pad_c(0));
-  padc_.push_back(pad_conf.pad_c(1));
-  padh_.push_back(pad_conf.pad_h(0));
-  padh_.push_back(pad_conf.pad_h(1));
-  padw_.push_back(pad_conf.pad_w(0));
-  padw_.push_back(pad_conf.pad_w(1));
+  padc_ = {pad_conf.pad_c(0), pad_conf.pad_c(1)};
+  padh_ = {pad_conf.pad_h(0), pad_conf.pad_h(1)};
+  padw_ = {pad_conf.pad_w(0), pad_conf.pad_w(1)};
 
   outDims_ = TensorShape(4);
   setOutDims(0);
@@ -49,21 +46,15 @@ bool PadLayer::init(const LayerMap& layerMap,
   createFunction(forward_,
                  "Pad",
                  FuncConfig()
-                     .set("cstart", padc_[0])
-                     .set("cend", padc_[1])
-                     .set("hstart", padh_[0])
-                     .set("hend", padh_[1])
-                     .set("wstart", padw_[0])
-                     .set("wend", padw_[1]));
+                     .set("channel", padc_)
+                     .set("height", padh_)
+                     .set("width", padw_));
   createFunction(backward_,
                  "PadGrad",
                  FuncConfig()
-                     .set("cstart", padc_[0])
-                     .set("cend", padc_[1])
-                     .set("hstart", padh_[0])
-                     .set("hend", padh_[1])
-                     .set("wstart", padw_[0])
-                     .set("wend", padw_[1]));
+                     .set("channel", padc_)
+                     .set("height", padh_)
+                     .set("width", padw_));
 
   return true;
 }
diff --git a/paddle/gserver/layers/PadLayer.h b/paddle/gserver/layers/PadLayer.h
index b2bbf28082e630aeb429ee997a1d43ce7ba05d1c..fe9388d8cc260ed599af0113361f4687f3f4a18b 100644
--- a/paddle/gserver/layers/PadLayer.h
+++ b/paddle/gserver/layers/PadLayer.h
@@ -38,9 +38,9 @@ protected:
   void setOutDims(const size_t batchSize);
   void setTensorDim(const size_t batchSize);
 
-  std::vector<int> padc_;
-  std::vector<int> padh_;
-  std::vector<int> padw_;
+  std::vector<uint32_t> padc_;
+  std::vector<uint32_t> padh_;
+  std::vector<uint32_t> padw_;
   TensorShape inDims_;
   TensorShape outDims_;
 };
diff --git a/paddle/utils/Any.h b/paddle/utils/Any.h
index 0352e9805425720edb165d08a93f05fe1dbe3892..99a0139accc4988f1e4cce45eeb688a6603c2c31 100644
--- a/paddle/utils/Any.h
+++ b/paddle/utils/Any.h
@@ -20,6 +20,7 @@ namespace paddle {
 // using std::any for C++ 17
 using std::any;
 using std::any_cast;
+using std::bad_any_cast;
 }  // namespace paddle
 
 #else
@@ -29,5 +30,6 @@ namespace paddle {
 // use linb::any for C++ 11
 using linb::any;
 using linb::any_cast;
+using linb::bad_any_cast;
 }  // namespace paddle
 #endif