The construction of national smart grid has been carried out, and the process of equipment intellectualization has been accelerated. However, the measurement of time parameters of high-voltage switch still adopts the traditional off-line mode, which increases the outage time of equipment and reduces the reliability of power supply. Firstly, this paper studies the characteristics of the RF signal of the high-voltage switch in the process of switching and closing, which provides a reference for the development of the prototype of the high-voltage switch characteristic RF detection system. Finally, a prototype of high-voltage switching characteristic radio frequency detection system is developed, including the selection of radio frequency antenna form and frequency band, data acquisition solutions, and the development of detection and evaluation software. The experimental results show that the frequency domain of the radio frequency signal emitted by the high voltage switch during the switching and closing process is very wide, and the upper limit can reach 2 GHz. The sample machine developed in this paper, the measurement uncertainty of pulse interval time and the amplitude consistency all meet the practical requirements of engineering.