The invention relates to a power transmission and transformation equipment state monitoring system security protection method based on trust chain transmission, which carries out credible transformation to a power transmission and transformation equipment state monitoring system through identity authentication, platform authentication, integrity measurement, trust chain transmission and other methods. A credible authentication service, an access actuation server and a centralized regulation server are deployed in a main station, and a monitoring terminal, a state information access controller, a state information access gateway machine and a state monitoring proxy are transformed into a credible monitoring terminal, a credible state information access controller, a credible state information access gateway machine and a credible state monitoring proxy, so that the whole monitoring system is constructed into a credible system. The system can effectively prevent malicious program attack, malicious code injection attack, physical data theft, network tapping, sniffing attack and the like, and protect the security of the monitoring system and an internal power grid system; and the invention also provides a trust chain transmission model which is used for proving that under trust chain transmission, as long as each level of a trust chain is credible, the whole system is credible.