In order to improve the standardization and informatization level of safety management for power plant, a new security system with multi schemes combined was proposed for power plant, based on the concept of layers of protection. This digital security system adopts a brand scheme that includes the alarm of electronic fence, infrared bijection, emergency button, as well as the linkage between boundary alarm and security video monitoring system. This system has been successfully applied in a large power plant, which can provide reference for the design of security system in power plant.