The low degree of automation and intelligence of existing general power system simulation software has greatly affected the efficiency of security and stability analysis. An intelligent simulation tool for a power gird based on PSASP is designed and developed according to the actual needs of engineers and technicians. The simulation software is optimized to improve work efficiency from three aspects: data analysis and processing, optimization of calculation function and automation of result analysis. The Dameng database system is introduced to realize the storage, calculation, query and sharing of massive data. The function of power station wiring diagram auto-graphing is developed to automatically achieve visual display of the connection relationship of elements. The function of operating mode data automatic generation is developed to form power flow data for mass operational modes. The function of automatic static safety analysis can automatically realize calculation of disconnection and the intelligent analysis and display of results. Finally, taking security and stability analysis of the Central China power grid as an example, the practical effect of power grid intelligent simulation tool is illustrated.