The reliability index and technical level of aerospace electromagnetic relay are extremely high. It has the irreplaceable advantages of high conversion depth, multi-channel synchronous conversion, high sensitivity, fast action, small size, low power consumption, large input-output ratio and strong anti-interference ability, so it is widely used in various fields of weapons and equipment, aerospace and national defense industry. According to incomplete statistics, a new tactical missile in the use of aerospace relays to 900, a synchronous satellite using aerospace relays up to about 1500, a type of launch vehicle control system alone used 354 aerospace electromagnetic relays of various types. Because of the important role of aerospace electromagnetic relay, as long as one relay fails, it may cause serious consequences and great losses. It can be seen that the storage reliability of aerospace electromagnetic relay directly affects the reliability of the whole national defense weapon equipment system and aerospace system.