The severe situation of food safety，caused by intentional adulteration and vicious contamination，has become a serious threat to social stability and economic development of China. Therefore，it is urgent and crucial to effectively improve the efficiency of food safety regulation and the level of food defense，and the fundamental and key problem needed to deal with is to eliminate the obvious information asymmetry between regulation authorities and food enterprises. Theoretical researches and practical experiences indicate that the whistleblowing mechanism，which has been widely applied in several fields such as antitrust and crime prevention，is an important and feasible measure to solve information asymmetry，improve regulation efficiency，save regulatory cost and increase social welfare. In order to deeper understanding about the whistleblowing mechanism of food safety，hence，we carry on game analysis about the behavior mechanism of insider，a former or current member of firm who has acquired information and proofs about the illegal，immoral，or illegitimate practices under the control of his employer，and the interaction of between the insider and regulation authorities in the context of food defense，and try to provide theoretical support for building and improving this kind of mechanism. We mainly investigate the factors influencing the insider’s whistleblowing decision and related effect on regulation efficiency，and then，explore the efficient and reliable ways that can enhance the regulation efficiency. Based on the research results，finally，we put forward some policies and suggestions which are helpful to improve food defense and guarantee social benefits.