Using the characteristics of micro-blog communication, a complex network based micro-blog communication traceability method is proposed in this paper. In this scheme, the forwarding and commenting tree is reconstructed firstly by restoring a micro-blog forwarding and commenting relationship. Then, a micro-blog topic forwarding and commenting relationship diagram is expanded and reconstructed. Finally, the traceability search system of the key users of the micro-blog topic is designed and the experiment proves that the proposed tracing method is able to search for the micro-blog key users.