Abstract: A mathematical model is built for the curved seam tracking problem of wheeled welding mobile robot used in shipbuilding and large spherical tank welding.A novel controller is designed which is based on the integral backstepping time-varying state feedback method and the system stability is proved with Laypunov method.In consideration of the fact that the rotating arc sensor can only measure the single orientation errors,the azimuth of the tracking trajectory is estimated based on the previous and current locations of the welding torch's front point.Not only the moving and rotating velocity of the robot is controlled,but also the moving velocity of the cross-slider is controlled,making the tracking more quickly and smoothly.In the end,the validity of the method is proved through numerical and practical movement simulations of the robot.