Power cable is an important equipment for power transmission, and the safe and reliable operation of the cable plays a vital role in the power system. With the diversification of cable operation scenarios, reliable online monitoring of cable operation status becomes an urgent problem to be solved. In this paper, the experimental model of cable spike discharge is designed, and the experimental platform of cable partial discharge is built. By carrying out cable partial discharge experiment, the time domain waveform of partial discharge acoustic signal is obtained. The characteristics and development law of sound signal during the development of cable discharge are obtained through analysis. On this basis, a set of on-line monitoring sensor equipment is developed, and it can help the maintenance personnel to locate the local discharge source successfully in the actual project, which is of great significance to the reliable monitoring of the running state of the cable.