Abstract: The Sockets programming model is intended to be a standard for TCP/IP networking，and the Winsock is an open interface for network programming under Microsoft Windows ,which has been built upon the Sockets programming model. At first,the basic concept of Winsock is introduced，then the structure of Winsock is analyzed,at last，an example programme is presented to illuminate the method of implementing TCP/IP network communication by Winsock.

Key words: Sockets；network communication；Windows Sockets；C/S , model；API