As the information and communication technology is widely used in the relay protection system, online maintenance method, which is based on highly information sharing, has become a new mode to improve the efficiency of relay protection maintenance. Firstly, this paper analyzes the efficiency and sufficiency of conventional maintenance method. Aiming to achieve overall and real-time state assessment as well as reliable and efficient relay protection maintenance, the demand of panoramic information and online maintenance is proposed. Furthermore, state information set and its composition and obtain way are discussed in this paper, while different online maintenance methods according to different categories of state information are also proposed. Based on the above information sets, this paper proposes an online maintenance system which can discover many faults of relay protection. Finally, considering both conventional and online maintenance methods, this paper describes a new mode for relay protection maintenance. This work is supported by National Natural Science Foundation of China (No. 51577073) and Science and Technology Project of China Southern Power Grid Co., Ltd. (No. GDKJXM20184472).