High voltage switchgear, isolating switch and other high voltage switch equipment in substation are all important equipment in transmission system. Their stable operation is necessary for the normal work of power grid, so the temperature monitoring of these equipment plays an important role in the whole power system. In this paper, we design a novel selfpowered wireless temperature sensor using the electric field inductive technology and propose a kind of structure of the substation equipment temperature monitoring system based on the novel sensor. Composed of self-powered wireless temperature sensing chip and electric field coupling plate, self-powered wireless temperature sensor can acquire temperature information of the substation equipment without any enteral power supply. Meanwhile, the self-powered wireless temperature sensor is applied to the temperature monitoring system, which can real-timely measure the temperatures of several points, such as cable joint, knife contact, high voltage switchgear contact or copper platoon connection point and so on. This system has advantages of low power consumption, high reliability and strong anti-jamming capability, and can effectively guarantees the safety of the substation equipment.