The tool plays an important role in cutting process. The aim of this paper is to investigate the effect of tool geometrical parameters on the chip formation and cutting force with orthogonal cutting models. The large deformation Rigid-visco-plastic FEM program DEFORM-2D(TM) is used, and thermo-mechanical coupling effect are considered. The chip separation from workpiece is implemented by remeshing. Contrary to traditional cutting simulation, the workpiece is moved and the tool is fixed, which is consistent with actual process. The effects of tool rake angle on the chip geometry and cutting force are analyzed. The simulated cutting forces are compared with results in other references. The research results are a help to cutting process study and cutting tool design.