In order to enhance the management of secondary equipment and improve the working efficiency of the operation and maintenance personnel, this paper studies and summarizes the key technologies of remote operation and maintenance of relay protection. The application of technologies such as power grid fault rapid analysis, secondary circuit visualization, real scene display and remote operation of secondary equipment, intelligent diagnosis of device failure and auxiliary decision of maintenance, etc. can realize the function of intelligent analysis of grid fault for dispatching, on-line diagnostics for maintenance and on-line monitoring for operation. The information sharing, business collaboration and lean management are ultimately achieved, the operation efficiency of equipment maintenance and the ability of power grid fault disposal are greatly enhanced. This work is supported by Science and Technology Project of State Grid Corporation of China (No. JBB17201500108) and Zhejiang Electric Power Co., LTD. Technology Project (No. 5211WZ15013Q).