Microblog，with unique characteristics of open，dynamic and collaborative communication，has become a new approach for governments at various levels to understand and press close to people，also solve people’s problems. This paper attempted to present the main manifestations of the communication innovation in China’s governmental affairs Microblog，and analyze the reasons and trends. The research found five types of communication innovation in governmental affairs Microblog，which are function innovation in publication-posting advice-execution，interaction innovation in transparent social governance，crisis management innovation in transmitting positive energy by linked information，international cooperation innovation in transnational dialogues of governmental affairs，and social governance innovation in application of big data，respectively. According to the analysis on reasons and trends of communication innovation，there are still prominent problems in this new media for governmental affairs，such as unclear function position，less rigorous information release，non-standard operation and maintenance，lack of supervision，assessment and accountability mechanism. Governmental affairs Microblog will undertake more social functions，including “stabilizer of emergency”，“aggregator of positive energy”，“catalyst towards public charity action”，“connector of social governance”.