As the insufficient of the length and depth of past power quality monitoring system, the paper proposes a 4G-based power quality monitoring system communication network. The paper analyzes and designs net-structure of 4G-based power quality monitoring system, expounds the safety and electromagnetic compatibility of 4G networks, and chooses a medium plate plant as the object of power quality monitoring. The result of monitoring shows that the 4G-based power quality monitoring system has lots of well properties, just as,data transmission rate, data packet loss rate, transmissionSstability and change of the power quality data. Meanwhile, the system has good engineering application value.