The equipment’s state monitoring and evaluation is the foundation of state maintenance. According to the technical features of smart substation, this paper researches on secondary equipments’ state monitoring and evaluation in smart substation. Switch state information is acquired with IEC61850, the switch port traffic, port to receiving light intensity, port to sending light intensity, working temperature and port error rate are selected as evaluation indicator of switch, and the switch state is evaluated comprehensively with the fuzzy comprehensive evaluation method. For the problem of preventing the protection of export trip circuit contact adhesion, failure, and forgetting the cast plate, the background monitoring system is designed in conjunction with the intelligent component to realize the inspection trip contact. For SV, GOOSE transceiver anomaly between the bay layer and process layer, it presents a dependency network packet analyzer diagnostic method to diagnose out a bay layer device or intelligent component failure.