This paper takes relay protection device for example to survey and analysis the secondary power equipment’s practical life, summarizes the major factors which influences the life of the secondary power equipment, influence mechanism and corresponding countermeasures, and aiming at 20 years life, building a stress-life accelerated life test method using the front conclusions based on weibull distribution and Peck model. At last, works out the basic parameter of accelerated life test. This paper provides the testing theoretical foundation of verifying the life of the secondary power equipment.