The opinion leaders of the network dominate the flow of a fairly large number of information,so it can be understand the propagation structure of the microblog platform by analyzing the relationship between them.This paper uses the data which collected in the Sina-microblog for analysis and processing by using the two-step cluster,so this can identify the opinion leaders in groups with social network features.Then,it can use the identified groups of opinion leaders to construct a network by social network analysis,and analyze the center and density of the network.It shows that the relationship of members of the network is not tight enough;but,it will be known that if the two ones who are not directly related need not so long to establish a connection,and identify the core members of the network.