In the OMG's COM/CORBA interworking specification, interworking between COM and CORBA is implemented via bridges. Though the interworking model is flexible, it needs heavy overheads which leads to poor performance. Moreover, there are problems in its object life-cycle mapping. It does not provide portability either. In this paper, a COM/CORBA interworking model is proposed based on multi-interface object integration method. In the new model, a client can directly access a foreign object, therefore interworking performance is improved remarkably. In addition, it enhances interworking transparency and provides application portability between COM and CORBA environments.