Abstract: The cutting induced residual stress of weak-rigidity parts has great influence on part distortion because of the weak rigidity and large material removal. So，the study of influence of residual stress on machining distortion is of momentous significance. The finite element model（FEM）of hub brake cap cutting process is established. The influence rules of the cutting parameters on the residual stress are obtained with the analysis of the residual stress distribution along with the depth of the workpiece caused by different cutting parameters. The rules are validated by experiments. At last，the influence rules of the residual stress on the machining distortion are obtained by the analysis of the machining distortion due to residual stress induced by different cutting parameter，which provide the basis of machining process optimization.

Key words: weak-rigidity parts, residual stress, machining distortion