diff --git a/paddle/api/Evaluator.cpp b/paddle/api/Evaluator.cpp
index 681e3a380912339c531c16c88f43255c2f34c32f..fcda6eaf031c02f2314298f88b3af2c08ba6fa11 100644
--- a/paddle/api/Evaluator.cpp
+++ b/paddle/api/Evaluator.cpp
@@ -37,7 +37,7 @@ std::vector<std::string> Evaluator::getNames() const {
 double Evaluator::getValue(const std::string name) const {
   paddle::Error err;
   double v = m->rawPtr->getValue(name, &err);
-  if (err) {
+  if (!err.isOK()) {
     throw std::runtime_error(err.msg());
   }
   return v;
diff --git a/paddle/gserver/activations/ActivationFunction.cpp b/paddle/gserver/activations/ActivationFunction.cpp
index a40530f41313be27dc1c2606501c6c00bed11c8b..81cc3c890b6d4ad048e4edc03208c85778244078 100644
--- a/paddle/gserver/activations/ActivationFunction.cpp
+++ b/paddle/gserver/activations/ActivationFunction.cpp
@@ -207,8 +207,8 @@ Error __must_check backward(Argument& act) {
     argument_.value->setData(act.value->getData() + offset, 1UL, size);
     argument_.grad->setData(act.grad->getData() + offset, 1UL, size);
 
-    Error status = softmax_.backward(argument_);
-    if (!status) return status;
+    Error err = softmax_.backward(argument_);
+    if (!err.isOK()) return err;
   }
   return Error();
 }
diff --git a/paddle/utils/Error.h b/paddle/utils/Error.h
index 27ddaab3f003110a2684a871a2de17afb473d660..7cde98306026ca1de76089749aaea265d151da33 100644
--- a/paddle/utils/Error.h
+++ b/paddle/utils/Error.h
@@ -126,9 +126,11 @@ public:
   }
 
   /**
-   * @brief operator bool, return True if there is something error.
+   * @brief check this status by glog.
+   * @note It is a temp method used during cleaning Paddle code. It will be
+   *       removed later.
    */
-  operator bool() const { return !this->isOK(); }
+  void check() const { CHECK(this->isOK()) << msg(); }
 
   /**
    * @brief isOK return True if there is no error.
@@ -136,13 +138,6 @@ public:
    */
   bool isOK() const { return msg_ == nullptr; }
 
-  /**
-   * @brief check this status by glog.
-   * @note It is a temp method used during cleaning Paddle code. It will be
-   *       removed later.
-   */
-  void check() const { CHECK(this->isOK()) << msg(); }
-
 private:
   std::shared_ptr<std::string> msg_;
 };
diff --git a/paddle/utils/tests/test_Error.cpp b/paddle/utils/tests/test_Error.cpp
index fdf326b17a1c8baa87e2a17fafae253565d1e699..6f311fa6b80191de1e11ce1f63c31b64fe2eeb80 100644
--- a/paddle/utils/tests/test_Error.cpp
+++ b/paddle/utils/tests/test_Error.cpp
@@ -18,17 +18,17 @@ limitations under the License. */
 
 TEST(Error, testAll) {
   paddle::Error error;
-  ASSERT_FALSE(error);
+  ASSERT_TRUE(error.isOK());
   error = paddle::Error("I'm the error");
-  ASSERT_TRUE(error);
+  ASSERT_FALSE(error.isOK());
   ASSERT_STREQ("I'm the error", error.msg());
 
   error = paddle::Error("error2");
-  ASSERT_TRUE(error);
+  ASSERT_FALSE(error.isOK());
   ASSERT_STREQ("error2", error.msg());
 
   int i = 3;
   auto error3 = paddle::Error("error%d", i);
-  ASSERT_TRUE(error3);
+  ASSERT_FALSE(error3.isOK());
   ASSERT_STREQ("error3", error3.msg());
 }