Abstract: In order to study the residual strain distribution law of rotating arc welding, the workpiece deformation is controlled and the residual stress and strain of the workpiece under the two kinds of restraint models are compared and analyzed. Firstly, the three-dimensional multi-body coupling model composed of weldment, workstation and fixture is established by setting the contact relation between the models. Then, by setting the normal pressure and displacement constraints on the node area of the workpiece, the external restraint force based on the above two models, ANSYS software was used to simulate the deformation of the rotary arc welding. The residual stress and strain curves of the two models were obtained and verified by experiments. The results show that the strain curves of the welded parts of the three-dimensional multi-body coupling model are closer to the test results, and the residual strain range and peak value of the welds are relatively gentle, which can provide reference for optimizing the welding fixture to control the deformation of the rotary arc welding.