The invention relates to a power network security research and judgment system which comprises an access source management module, an application management module, a data management module, a risk research and judgment module, a comprehensive display module and a user management module. The data management module carries out unified data analysis, the risk research and judgment module sets risk rules and carries out automatic research and judgment, the comprehensive display module carries out safety risk statistical display, and the power network safety research and judgment method is provided on the basis. According to the method, plug-ins do not need to be installed on the network application, the current risk condition of the network application can be quickly mastered, the problems of high false alarm rate, risk problem omission and the like existing in a single data source are solved, the risk identification accuracy can be effectively improved, and the system operation and maintenance safety is improved.