Aiming at the problem of massively storing massive monitoring data of mass power quality, a new database design method based on HBase for dual-column power quality monitoring system is proposed. It finds and designs the optimal power quality online monitoring data storage structure by applying column family storage architecture of the HBase to the efficient storage of complex power quality online monitoring data and then building storage optimization functions. Finally, the reading and writing time of several different column families are compared. Experiments show that the proposed double-column family of power quality monitoring data storage design method can store massive power quality monitoring data efficiently and has good feasibility. This work is supported by National Natural Science Foundation of China (No. 51567008 and No. 51867009), Foundation Plan for Distinguished Young Scholars in Jiangxi Province (No. 20162BCB23045), Natural Science Foundation of Jiangxi Province (No. 20171BAB206044) and Science and Technology Research Project of Jiangxi Provincial Science and Technology Department (No. GJJ160471).