Abstract: A finite element model ( FEM ) of prestress cutting for titanium alloy TC4 was established to explore the saw-tooth chip forming process and distribution of residual stress to machined surface at different prestresses. Then the simulation value and experimental test value were compared. The results show that the distribution status and value of residual stress on machined surface of titanium alloy can be adjusted by the prestressed cutting method in cutting process, within the elastic deformation limit of titanium alloy, the higher the applied prestress was, the higher the value of compressive residual stress in surface layer was and the deeper the layer of compressive residual stress distribution was. Prestress showed an indistinctive effect on the saw-tooth chip forming process. The numerical simulation values were in good agreement with the experimental values.