By constructing influence model for communication effect of food safety risk in social media environment, the influences of different response manners taken by relevant enterprises on consumers’ cognition and purchasing intention are analyzed, and influence mechanisms of response effort level, interaction and content reliability on consumers’ attitudes are revealed. Based on quasi-experimental study with three kinds of response effort levels, it is found that content reliability, interaction and effort degree of enterprise response under negative information of food safety event have significant impacts on communication effect and consumers’ purchasing intention.