Abstract: Aiming at the problems of poor real-time performance and low sampling accuracy of power quality monitoring system in coal mine grid, a design scheme for the power quality monitoring system based on STM32F767IGT6 microprocessor is proposed in this paper. On the basis of the three-layer network structure, the voltage and current acquisition circuit is built; the high-precision and real-time PT and CT are selected to collect voltage and current signals and then transmit them to the STM32F767IGT6 chip for calculation, analysis and logical processing. The power quality monitoring system is built based on the digital signal processing chip to realize real-time display of the power quality monitoring data. Finally the test verification is completed. The test results show that the system can realize efficient, real-time and accurate monitoring of the power quality data, and it meets the requirements of system design.