The invention discloses a method and system for inquiring about maintenance information of a relay protection device. The method includes the steps of obtaining image information of a unique two-dimension code corresponding to the relay protection device to be inquired of, converting the image information to an ASCII code according to the encoding rule of two-dimension codes, generating identification information of the relay protection device to be inquired of according to the ASCII code, sending the identification information to a server, sending the server a request for inquiring about the maintenance information of the relay protection device corresponding to the identification information, obtaining the inquiry result which is fed back by the server and contains the maintenance information, and displaying the inquiry result. By means of the method or system, the maintenance information of the relay protection device can be inquired about through a network, and the efficiency of inquiring about the maintenance information of the relay protection device is improved.