Considering the operational condition and maintenance mode of an on-site protection device in a substation, a novel closed-loop test and equipment management intelligent platform is proposed. The proposed intelligent platform effectively avoids the tedious process of the traditional closed-loop test mode, and solves the equipment management problem of the on-site protection device. The platform includes three key aspects: an information acquisition and display method, a ring network communication criterion among on-site protection sub systems, and an intelligent implementation technology of an automatic test process. The proposed intelligent platform has been used in Ningxia Shizuishan Power Supply Company for a long time, with stable and reliable operation and remarkable effect. The application results show that the proposed platform ensures the quality of the closed-loop test of the on-site protection device, greatly reduces the workload of the operation and maintenance personnel, and effectively reduces the operational and maintenance cost. This work is supported by the Science and Technology Project of State Grid Corporation of China (No. 5229DK18002S) and National Key Research and Development Program of China (No. 2017YFB0902800).