With the development of the Internet， “information sharing” has become a major reason for people to use and participate in the network. This paper argues that the network information sharing behavior is the behavior of the network users based on some kind of psychology to spread the information that they own through the network platform to the outside world by specific means. In order to make clear about the current research situation and give some enlightenment for the future research， this paper summarizes the existing research contents from the aspects of the concept of network information sharing behavior， the reasons why network users share information， the behavior characteristics of information sharing and the characteristics of sharer .