In order to solve the problem that pipe robot is difficult to detect defects in pipe and has poor passability, an adaptive pipe robot for inspecting and polishing pipe inner wall was designed, and its passability in straight pipe, bend pipe and obstacle pipe was studied. The structure scheme of the pipeline robot was proposed, and the characteristics of its driving device and operating device were analyzed; the kinematics model of the robot was established, and the mechanical state, geometric constraint and motion characteristics of the robot moving in different pipes were analyzed in combination with the force of the structure in the pipeline; by using ADAMS simulation software and integrated simulation method, the passability of the robot in the pipeline was simulated and analyzed . The results show that the robot can pass through horizontal straight pipe, bend pipe and pipe with 10 mm high annular barrier, but the speed, pressure and contact force of the wheel fluctuate to some degree; when passing through the bend pipe, the differential speed of the inside and outside wheel and the outside expanding diameter reducing mechanism are adopted to reduce the internal consumption and increase the adhesion force.