Abstract: Taking the inspection robot of underground substation as the basic service platform, using the illusory engine UE4 as the development tool, and with the help of UE4 programming language blueprint, a digital twin system of inspection robot of underground substation of coal mine based on UE4 is designed. The system can remotely control the inspection robot to complete fixed-point and automatic inspection, display the inspection environment in three dimensions, receive the inspection data collected, analyze and display the data. The whole system architecture and each functional module are described in detail. The operation results show that the digital twin system of inspection robot realizes the inspection maintenance cooperative operation control of intelligent inspection robot; the system runs stably, can replace manual to complete the efficient inspection and management of underground substation, improve the production efficiency of coal mine.