There are many requirements for intelligent, visual and remote operation and maintenance personnel of a substation. To help satisfy these, key technologies such as image acquisition, image recognition, infrared temperature measurement and diagnosis, intelligent patrol inspection, intelligent linkage, comprehensive diagnosis and visual display are studied. A joint inspection system based on artificial intelligence analysis technology is developed and applied, including functions of joint inspection, comprehensive perception, intelligent linkage, diagnostic analysis and comprehensive display, etc. The system integrates multi-source data of the whole station, realizes comprehensive equipment state perception through a variety of advanced sensors and acquisition equipment, uses laser navigation wheeled robots, rail robots, and fixed-point cameras. These form a core for building a three-dimensional inspection system to achieve the goals of intelligent inspection, intelligent operation, intelligent linkage and intelligent security. By optimizing the joint inspection strategy and applying it to the State Grid Smart Substation Project, good results are obtained. This work is supported by the Science and Technology of State Grid Corporation of China (No. 520940180036) “Research on Secondary System Architecture and Key Equipment of Third-generation Intelligent Substation”.