This paper presents the process model of micro blog opinion formation.The study make a empirical analysis of the public opinion in Micro blog platform about the"‘Yao' case" events, aim at find out the interaction mechanisms of information fragments, topic,opinion leaders and Audience-segmentation of fan base.And on that basis analysis the interactive mechanism among opinion leaders, the interactive mechanism between opinion leaders and Grassroots users,and the interactive mechanism among Grassroots users. <<