When regularly inspecting the spherical tank in service, it is necessary to build scaffolds inside and outside the spherical tank, and the non-destructive inspection should be completed by manual operation.So the workload of inspectors is large and the testing efficiency is low. It is necessary to develop an automatic detection system to replace manual detection. On the basis of summarizing the research status of wall-climbing robot and detection robot at home and abroad, a wall-climbing detection robot suitable for large spherical tank was proposed. The robot has macro video detection, ultrasonic thickness measurement, magnetic particle detection and other functions, which can improve the work efficiency and reduce the labor intensity of workers, and has a great application prospect.