采用顺序热力耦合的方法建模，通过正交试验，利用ABAQUS软件分析了铝-镁异种合金搅拌摩擦搭接焊中焊接速度、搭接量、搅拌头转速对残余应力的影响，获得最优的工艺参数，通过试验验证模拟结果的准确性，并研究焊接速度、搭接量对残余应力的影响规律。结果表明：搅拌摩擦搭接焊的最优参数为焊接速度60 mm·min^-1、搭接量60 mm、搅拌头转速1 400 r·min^-1；在不同焊接工艺下，热循环曲线和残余应力的模拟结果与试验结果相吻合，相对误差分别小于7.5%和8.4%，验证了数值模拟结果的准确性；最大残余应力出现在焊缝末端的搭接面处，最优焊接工艺下的最大残余应力为137.7 MPa；与搅拌头转速相比，焊接速度与搭接量对残余应力的影响较大，随着焊接速度的增大，纵向残余压应力峰值升高，压应力作用范围变窄，而随着搭接量的增加，纵向残余压应力峰值降低，压应力作用范围变宽。

The sequential thermo-mechanical coupling method was used to establish the model,and through the orthogonal experiment, the effects of welding speed, overlap amount and stirring tool rotation speed of friction stir lap welding on the residual stress of Al-Mg dissimilar alloy were analyzed by ABAQUS software. The optimal process parameters were obtained. The simulation was verified by tests. The effects of welding speed and overlap amount on the residual stress were studied. The results show that the optimal parameters of friction stir lap welding were welding speed of 60 mm·min^-1, overlap amount of 60 mm and stirring tool rotation speed of 1 400 r·min^-1. In different welding processes, the simulation of thermal cycle curves and residual stress were consistent with the experimental results, and the relative errors were less than 7.5% and 8.4%, respectively, which verified the accuracy of the simulation. The maximum residual stress appeared at the overlap surface at the end of the weld, and the maximum longitudinal residual stress in the optimal welding process was 137.7 MPa. Compared with the rotation speed of the stirring tool, the welding speed and the overlap amount had a great influence on the residual stress. With increasing welding speed, the peak value of the longitudinal residual compressive stress increased,and the range of compressive stress became narrower; with increasing overlap amount, the peak value of longitudinal residual compressive stress decreased and the range of compressive stress became wider.