The invention discloses a system for automatically maintaining a PI measuring point of a power system, comprising servers of each production system, a PI real-time data server and each client terminal. The system for automatically maintaining the PI measuring point of the power system is characterized by further comprising a PI model data server stored with model data; the PI real-time data server and the PI model data server are respectively connected with each client terminal to realize data transmission, each client terminal is further provided with a PI application unit, the servers of each production system form an outer net; an inter net consists the PI real-time data server, the PI module data server and each client terminal, and the safe data exchange between the outer net and the inter net is realized through a physical isolating apparatus. Compared with the prior art, the invention is additionally provided with the PI model data server to store the model data in the power system, therefore, when in use, the client terminal firstly sends an access request to the PI model data server according to the PI measuring point logic required by the PI application, and then realizes the automatic extraction of the PI measuring point through querying language written in the PI model data server.