diff --git a/mace/kernels/activation.h b/mace/kernels/activation.h
index c9f8dac5873a3cedcac4ff4cddd92c89b91ef9a3..72e52b67cfef1e3a230c78fb94edc72fd5ca397f 100644
--- a/mace/kernels/activation.h
+++ b/mace/kernels/activation.h
@@ -116,7 +116,7 @@ class ActivationFunctor {
     const T *input_ptr = input->data<T>();
     T *output_ptr = output->mutable_data<T>();
     if (activation_ == PRELU) {
-      MACE_CHECK(alpha != nullptr) << "PReLU's alpha parameter shouldn't be null";
+      MACE_CHECK_NOTNULL(alpha);
       const T *alpha_ptr = alpha->data<T>();
       PReLUActivation(input_ptr, output->size(), input->dim(3), alpha_ptr, output_ptr); 
     } else {
diff --git a/mace/kernels/opencl/activation_opencl.cc b/mace/kernels/opencl/activation_opencl.cc
index 9521f82e3bc6ca25feb2aa8f299e3f604279e1c5..75922a9eb17af3b9790a283efaf3b1d9581c2f8c 100644
--- a/mace/kernels/opencl/activation_opencl.cc
+++ b/mace/kernels/opencl/activation_opencl.cc
@@ -62,7 +62,7 @@ void ActivationFunctor<DeviceType::OPENCL, T>::operator()(const Tensor *input,
     int idx = 0;
     kernel_.setArg(idx++, *(input->opencl_image()));
     if (activation_ == PRELU) {
-      MACE_CHECK(alpha != nullptr) << "PReLU's alpha parameter shouldn't be null";
+      MACE_CHECK_NOTNULL(alpha);
       kernel_.setArg(idx++, *(alpha->opencl_image()));
     }
     kernel_.setArg(idx++, static_cast<float>(relux_max_limit_));