Instant Message is a fundamental application of the Internet in China with a great number of users. This paper explores the development of IM as a new media. In 2009，Chinese network continues to expand the scope of instant messaging users has the number of more than 270 million，concentrating in 30 years of age. The typical characteristics of IM in China are social network service and trans-platform. In the dissemination function and social impact，the IM has powerful real-time communication interpersonal，group communication capabilities，through its powerful communication features and a large user base. The mobilization of IM playing an important role in some affairs has the serious impact on community in China.