Abstract：Distributed Power Quality Information System (DPQIS) adopts the distributed technology to design and implementation the Power Quality Information System (PQIS). The construction of power quality online monitoring system is an important method for improving the quality of electricity and ensuring the safe supply of power grid. The conventional PQIS includes the following subsystems, such as data collection, data computation, and data analysis. With the number of monitoring sites rapidly increase, the load of the above subsystems increases multiply. Due to the processing ability limitation of the system, the number of monitoring sites of the system is limited. The performance bottleneck of the system should be solved urgently. The distributed architecture is employed to design, utilize distributed processing system for the data collection, the distributed database is used for data storage, distributed computing is taken for data computation, and WebService interface is adopted for encapsulating data access; the processing ability and response speed of the system are economically and effectively improved. Then the upper limit problem of server load is resolved and the demand on massively increasing monitoring sites for electric supply company in the future is satisfied.