In order to solve the problem of underground power supply system grade tripping in Shennong Coal Industry, the composition of the underground power supply system was analyzed, the overall scheme of the underground power supply system monitoring system was proposed, the design of the monitoring system hardware and software was carried out, and the power supply monitoring system was tested in trial operation. The results showed that the underground power supply monitoring system of Shennong Coal Industry can realize the monitoring and control of the underground power supply system, the system operation was stable and reliable, and solved the problem of underground over-step tripping.