diff --git a/docs/development/adding_a_new_op.md b/docs/development/adding_a_new_op.md
index eda612d34739731b3431d8d2657ef7d693c619c3..1b1910db81c7902bf56f91199d672dc5ec00e3d1 100644
--- a/docs/development/adding_a_new_op.md
+++ b/docs/development/adding_a_new_op.md
@@ -82,7 +82,37 @@ void Register_My_Custom_Op(OperatorRegistryBase *op_registry) {
 }  // namespace mace
 
 ```
-And then register the new Op in `mace/core/operator.cc`.
+And then register the new Op in `mace/ops/ops_register.cc`.
+```
+#include "mace/ops/ops_register.h"
+
+namespace mace {
+
+namespace ops {
+// Keep in lexicographical order
+
+...
+
+extern void Register_My_Custom_Op(OperatorRegistryBase *op_registry);
+
+...
+
+}  // namespace ops
+
+
+OperatorRegistry::OperatorRegistry() : OperatorRegistryBase() {
+  // Keep in lexicographical order
+
+  ...
+
+  ops::Register_My_Custom_Op(this);
+
+  ...
+
+}
+
+}  // namespace mace
+```
 
 Implement the Op kernel code
 ----------------------------