Architecture of power quality monitoring System on Chip (SoC) is proposed. The proposed SoC integrates several function blocks such as signal processing, power quality parameter calculation, wave recording, control and communication etc. These blocks exchang data with each other by using on-chip high speed data bus. As various calculation standard methods are implemented using hardware, the proposed SoC simplifies the duplicate efforts of device manufacturer, and improves reliability and consistency. Based on the SoC, handheld monitoring device can be developed and widely used in the area of new energy device and Electric vehicle charging etc.