The research focuses on analyzing the deformation of workpieces induced by residual stresses，the three-dimensional finite element milling model is established， taking into account the influence of residual stress caused by the rate of the back-cutting amount on the deformation，the simulated residual stress is integrated into the model，the relationship between the simulated residual stress and deformation is examined， and the simulation reliability is verified through experiments. The results indicate that as the tooth increases， the residual compressive stress on the surface of the workpiece（d=0） in the X and Y directions correspindingly increases， and the residual stress remains relatively unchanged when the distance between the test point and the surface exceeds 10μm. Wthe the increase in the number of baak-cutting tools，the residual stress on the surface of the workpiece in the X and Y directions increases accordingly. The deformation of the surface layer escalates with the rise in the feed rate of each tooth and also increases with the amount of back-cutting. A comparison of simulation and test results indicates that the maching deformation trends are fundamentally similar，thereby confirming the reliablity of the modeling.