Wireless passive current temperature sensor is to realize the needs of intelligent and automatic low-voltage distribution network, comprehensive data acquisition and monitoring is necessary. Through real-time online monitoring of the temperature, current and voltage of cables and bus bars, early hidden dangers can be obtained to ensure the safety of users. The passive composite sensor uses the electromagnetic energy around the transmission line to obtain electric energy, online monitoring the temperature and current of the cable, combined with wireless communication, to complete fast and accurate online measurement and save the shackles of the cable, and realize the function of wireless suitable for on-line monitoring of temperature and current transmission conductor in low voltage switch gear. The sensor is not in direct contact with the surface of the electrical equipment, and its built-in analog temperature sensor senses the ambient temperature of the contact surface and gets the corresponding voltage signal. According to the relationship between the voltage signal and no induction, the surface temperature of the live equipment can be determined. Non direct contact, electric field induction is used to detect whether the line is charged,and to detect whether the line is charged when there is no load and no current passing through.