Abstract: Based on the understanding of the definition of EC(electronic commerce)and intelligent agent ,this paper analyses the EC that focuses on business.The support from the middleware technology is drawn to dispel roaming,CORBA,which is one of the middleware technology,and also article discusses CORBA and the distributed tier structure,and ORB,IIOP,IDL.The purpose of this article is to inquire the distributed object’s invocation ORB and IIOP and to discuss the distributed tier structure’s application.