本系统是为方便企业内部进行简单办公，方便员工进行交流为基础，为企业提供较为完善的即时沟通和实时协作的解决方案。(This system uses Java language and eclipse as the basic development environment, using the software refactoring development approach, the original system design is optimized, by using the principle of lan communication mechanism (that is, through direct inheritance thread class to build a multi-threaded), realizes the network chat server and network chat client program. Java uses the common programming method of the network, socket socket, to set up the server so that the server can read and reply and forward the client messages. eclipse enables the client to communicate with the client by establishing a connection with the server. on the basis of the existing network, it is necessary to study a secure, private and regional instant communication tool. The significance and feasibility of the research are analyzed, and the prospects of ;lan chat software are presented.)