Abstract: New idea to control welding residual stress and distortion with trailing impactive electromagnetic force was given.Its feasibility was discussed by simulaion with the finite element analysis software ANSYS in the case of using flat spiral coil.The idea is the following:the inductor is located near the welding torch over the weldment and moved with the welding torch during welding.There is the rapidly changing current with high peak value in the inductor. And then there is the changing magnetic flux and the erratic current in the weldment.The electromagnetic force is gene rated between the inductor and the weldment.The welding residual stress and distortion will be controlled if the high temperature weld and the metal near the weld can be extended by the electromagnetic force.The simulation results show that the weldment is repelled by the coil owing to the axial electromagnetic force of flat spiral coil.And high temperature metal is able to be extended by electromagnetic force.Therefore, the welding residual stress and strain could be controlled based on electromagnetic force.