Aiming at the problem of high temperature fault of switch cabinet, we analyzed the deficiency of the existing temperature measurement method. We designed a kind of flexible anti-metal UHF RFID temperature tag by studying the structure and characteristics of the tag, and designed a UHF reader, a wireless repeater, and the software of the system, then built a switch cabinet temperature monitoring system based on the temperature tags. The system was verificated in 220kV electricity substation of Zhangjiakou electrical power company at zhaochuan. It proved that, the system could locate the measured point precisely by the EPC code of temperature tag. Temperature tags could reflect the real measured temperature without hidden security danger. The system has unified generalization significance.