The application of online stability assessment and decisionmaking system is one important method to improve the power system stability. After many years study, China has developed the system and applied in many power system companies. The system play important role in actual operation, but some questions should be further studied to improve adaptability. Based on the system's current situation and actual requirement, the paper presents the main function and existed question of this system and put forward further studied functions, which include the steady state analysis, automatically identification of weak area and key fault, the future stability prediction, online stability composite quantification assessment and adaptability analysis of stability control strategy. The paper also presents the possible implementation approach.