Abstract: Because of the influence of different error sources,the end of the welding gun doesn't follow predefined trajectory.An additional movement approach was presented to compensate position and orientation errors for each joint of the welding robot which caused small perturbation on the welding gun so that the error was eliminated.Since there were serious coupled interactions between kinematic pairs of the joints of 6-DOF welding robot,error compensation model was established based on small error assumption by analyzing the relationship between the robot coordinate system.The value of error compensation for each joint of the robot can be calculated accurately through the mathematical model.The correctness of decoupling methods and modeling presented in this paper were verified by the simulation analysis.The results showed that the algorithm can effectively reduce the position and orientation errors for the end of welding gun,which offered an effective theory foundation for the control of the pose accuracy in the welding robot.