The invention provides a system for evaluating the state of a secondary device of a power grid intelligent substation. The system comprises the intelligent substation, a communication keeping main station, a full-dimension management system, a production management system and the secondary device of a spacer layer of the intelligent substation. The secondary device is connected with a communication keeping sub-station of the intelligent substation. The communication keeping main station obtains the on-line monitor information of the secondary device in the mode that the communication keeping main station calls the communication keeping sub-station, and the on-line monitor information and self-detection data of the secondary device are together sent to the full-dimension management system. The full-dimension management system evaluates the state of the secondary device by adopting different model algorithms. By means of the system and method for evaluating the state of the secondary device of the power grid intelligent substation, a monitor and state evaluation module of the secondary device of the intelligent substation is built in the full-dimension management system, then the state evaluation on the secondary device of the intelligent substation based on an information infusion model and method can be achieved, and the investment and maintenance cost is lowered greatly.