Abstract:With the development of economy, the information exchange speed become more and more important. Today, as the tool of electronic data exchange: the EDI technology is the keystone. The instruction of the basic knowledge of EDI, the communication network of EDI is detailed. On the core technical of certain EDI software engine, the protocol module and protocol stack's architecture and realize are expatiated. The protocol stack can support many kinds of protocols, have favorable expansibility and maintainability.