Firstly, starting from the definition and classification of insider threats, this paper combs and analyzes the security protection methods of insider threats developed on the basis of general information systems, Then combining with the specific business analysis of the power information physical system (CPPS), it points out the insider threat challenges faced, and summarizes the research status of CPPs insider threat protection from the aspects of safety regulation guidance, error prevention technology research, domain knowledge application, authority allocation research and data leakage protection; Finally, comparing the differences between CPPs and general information systems, this paper puts forward the characteristics of using CPPs to carry specific business, designs targeted protection measures against insider threats, and finally looks forward to the application prospect of blockchain technology and zero trust in related fields.