This article analyses the principle and characteristics of I/O multiplexing models. It uses the socket's asynchronous communication to solve the problem of insufficient number of concurrent when Windows platform communicates with Linux platform. And the whole system adopts Client/Server model to build cross-platform asynchronous communication program. The server uses the epoll model provided by Linux and the client uses the AsyncCallBack provided by.NET to realize the cross-platform asynchronous communication. In addition, the program combines with the multithreading programming method to deal with the display problem of the client. From the observation of communication process, the server can receive data sent by multiple clients in the meantime and return data to them. In conclusion, with the using of the epoll interface, Linux server's concurrency is improved. For this reason, the real-time performance of the network communication between Windows and Linux platforms is also improved.