Abstract: A type of avoiding short circuit override trip system device based on stage current protection was put forward in this paper.When short circuit occurs in any place,switch protector at the short circuit node does not occur override trip accident by senting corresponding locking signal to its upper level and lower level switch,and it can be quickly cut off the short-circuit in the case of breaker rejecting act,which effectively protect the nomal operation of underground power supply lines and ensure the safety production of coal enterprises.