Following the outburst of mass disturbances in China，there emerging some new agents who play the role of brokers in mass disturbances. After the brokers are involved in mass disturbances，the form and content of mass disturbances display huge changes. Based on the framework of game theory，this report analyze the behavioral characteristics in mass disturbances，integrated with studies of four cases，this report put forward that，the defects of institutions and the capability failure of government governance caused the emergence of brokers in mass disturbance. We should distinguish differences between the constructive roles of social intermediary organizations and individuals with those destructive roles of brokers when dealing with mass disturbances. Those brokers，with the aim of getting benefits，by means of expanding social costs，always aggravate the destruction of mass disturbances. In order to get rid of the brokers in mass disturbances，the roots lies in to eliminate the bases of mass disturbances；the status and roles of government should be fixed within the framework of rule of law；the governing capability of government，especially the grass-root governments should be improved；social intermediary organizations and individuals should be regulated properly；early warning systems and corresponding plans should be formulated.