The expressiveness of current CORBA IDL is poor. Semantic properties of distributed objects can't be documented formally. The automation of the software development in CORBA is limited to the generation of the stub and skeleton that support basic functions. A kind of mechanism for customizing the dispatching and layering strategies of distributed objects is provided through extending the annotations used for describing objects behavior in IDL files. The mechanism not only improves time and space performance of applications, but also has no effect on portability and interoperability of applications. Moreover, a design pattern to resolve similar problems is presented by extending CORBA IDL.