In order to meet the development requirements of unmanned inspection of railway substation, improve the quality and efficiency of inspection work, a robot for indoor inspection of substation was designed. It was mainly composed of mobile car, lifting assembly, operating assembly, control cabinet. The mechanical structure of each part was introduced and the workflow of the inspection robot was described. The design realizes the functions of overall movement, platform lifting, camera shooting and manipulator operating switch. The coordinate system was established, the conversion relationship between each coordinate system was analyzed, the camera parameters calibration and handeye calibration were carried out, and the displacement value of the manipulator to the target point was calculated. The test results show that the robot could complete the inspection of the electrical control cabinet and receive the remote command to open and close the electrical switch. The developed inspection robot can reduce the work intensity of inspection personnel and improve the inspection efficiency.