The invention belongs to the technical field of a nuclear power plant control system and specifically relates to a nuclear power plant control system temporary control change online management system.The system comprises a data server, a network server and user terminals. The data server is used for analyzing DCS configuration data and DCS function drawings, generating risk rule data and storingrelated data real-time states. The network server is used for users to access interfaces, realizing a temporary control change process and carrying out data operation and call functions. All user terminals are used for accessing the network server through a company inner network, realizing functions of initiating, checking, approving and querying the temporary control change and displaying risks existing in the change within right display areas of pages of initiating, checking and approving links. According to the system, a temporary control change management process is electronized, and influences of control system configuration data module states on the operation of sets are displayed in a visual mode.