Currently the massive power quality monitoring data are stored in the centralized database of the monitoring master station, the problems such as large storage space; low query retrieval speed; low reliability and poor scalability will be caused. This paper proposes a data management scheme for massive power quality monitoring data based on the distributed database system. The monitoring data of different power quality indexes are stored in the distributed servers of the existing monitoring sub-stations; the server of monitoring master station is used for storing data characteristics value and data indexes, it is also used for unified management of distributed database system. The scheme takes full advantage of each servers storage space and network bandwidth, and saves the storage space and improves the access efficiency.