Abstract: Based on the thermo-mechanical coupling FEM theory, the welding distortion of joint lever was simulated by software MARC and the welding test was carried out. It shows better fitness between the numerical simulation result and experiment result. The error is only 4.8% which verifies the accuracy of the FE model. The elasticity anti-distortion facility was designed on the basis of the simulation data. The optimal parameters were obtained by numerical simulation of the joint lever with the facility and were applied to the test in which the ideal sample was acquired. The result shows that the maximum welding distortion of the joint lever is 9.85 mm when the facility is not applied. However, when the facility is used, the reduction of the middle rings and the side rings is 7 mm and 4 mm respectively, the maximum welding distortion is reduced by 82.4% to 1.73 mm. Thus, the welding distortion has been well controlled.