Social risks caused by emergencies may cause social conflicts or even endanger social stability through the spread and amplification of social networks. It is of great significance to explore the information mechanism of social risk amplification for effective prediction, identification and control of social risks. The factors that affect the individual risk perception amplification in the emergency situation were combed from the social level and the individual level, the theoretical model and mathematical model of the information mechanism of the social risk amplification of the emergency and the dynamic evolution model of the social risk amplification of the emergency were constructed based on the multi-agent modeling method. In the basis of coupling network model, the information mechanism of the official media and the unofficial media to amplify the public's social risk perception, as well as the regulatory role of the public's trust, was discussed so as to have a deeper exploration on the mechanism of social risk amplification of emergencies .The model constructed in this paper can theoretically insight into the complex interaction and influence relationship between systems, and the experimental results based on the coupled network model can reflect the reality more accurately, providing valuable suggestions for managers to deal with social risks in emergencies.