This paper presents a new design scheme of temperature on-line monitoring system of high voltage circuit breaker based on wireless communication. The advanced temperature sensor（DS18B20） is adopted to sample real-time data. The data are then sent to remote terminals combing wireless transmission with wired one and the monitoring software gives alert signal when temperature is abnormal. The wireless transmission uses data relaying to enhance the signal and dynamically set relay substation by statistical method， optimizing the communication network. The design of the hardware and software on wireless communication and anti-interference techniques are described in detail. The equipment has been practically applied with good effect.