A prototype of out-pipe anticorrosive robot was developed by the authors. The anticorrosive robot can complete the anticorrosion task of a steel-made pipe for transport oil and natural gas underground to substitute human beings. The structure composition and working principles of the anticorrosive robot was introduced and a design scheme of a double chain-wheel walking driving mechanism and the robot circumferential motion system was proposed based on incomplete-roller chain drive mechanism. And the motion performance of the circumferential motion system and walking mechanism was analyzed. The robot has good performance of obstacle crossing, swerving and circumferential motion. The results show that the theoretical analysis is similar to the experimental ones. And it meets the demands of anticorrosion construction. 