In order to make on-line monitoring on the temperature of high voltage switch circuit breakerand find outthermal fault in time. This paper puts forward a new method with radio frequency and magnetic saturation power supply technology to make on-line monitoring on the temperature of high voltage switch circuit breaker, it designs the high voltage switch circuit breaker contact temperature online monitoring device. The device mainly includes monolithic temperature collector and data receiver, they transmit data wirelessly, and this makes high temperature monitoring terminal and the data receiving terminal completely electrical isolated. Integrated temperature collector doesn’t need external power supply, it uses small CT saturation technology for continuous power. The experiment shows that the temperature error is ±2°C, it can meet online temperature monitoring requirements of high voltage switch circuit breaker contact.