The research and development of default value development and management platform of nuclear power plant control system can realize the functions of default value analysis, value selection, query and data management. The software standardizes the process and judgment factors of default value analysis process, makes qualitative and quantitative judgment on value selection factors, and combines the value selection algorithm embedded in the software, The auxiliary designer can automatically get the default value. The use of software can effectively improve the rationality and standardization of default value analysis. The software platform solves the problems of different default value analysis standards and chaotic data management in nuclear power plants. As the first special software for signal default value analysis and management of nuclear power control system in China, it has improved the intelligent level of the third generation nuclear power HPR1000.