Abstract: Aiming at the crawling robot used in the nondestructive testing of industrial pipeline welds, this paper compares and analyzes the surface motion stability of the wheeled crawling robot. On the basis of comparative analysis of the influence of different number of rounds on the crawling robot, the theoretical mathematical model establishment, prototype design, numerical simulation and experimental verification of the wheeled crawling robot are carried out. The test results show that the 4-wheel crawling robot has a smaller center height variation range and rate of change than the 3-wheel crawling robot during the movement in the curved pipeline, and has better surface movement stability. It can ensure the stability requirements of precision defect detection instruments, and provide technical support for the realization of remote automatic high-precision detection inside curved pipelines.