The power quality monitoring system (PQMS) is the important means to timely detect and assess power quality problems. Firstly this paper reviews the current research status of PQMS overall architecture scheme, power quality monitoring communication system and monitoring center software. On this basis the problems in existing PQMS such as the lack of perfect and unified communication standard, the lack of interaction and reusability among the related systems, the lack of effectively management and exploitation of massive monitoring data, the lack of supporting for the parties involved to use the systems simultaneously are analyzed. Then the importance of power quality information platform (PQIP) in the smart grid is expounded. Finally the development trends of exploring monitoring data, improving compatibility and openness, and the cloud computing based architecture in the future PQIP platform are proposed.