With hardened steel 65Mn as raw material, by using the finite element analysis (FEA) software Deform-3D, the hard machining of hardened steel model was constructed. The different cutting speeds for turning hardened steel 65Mn process were simulated, and the simulation results of cutting forces and cutting temperature and surface stress were analyzed in changes with increasing of the cutting speed and temperature during turning machining, which provided guidance for realizing optimization of process parameters. The results show that the maximum cutting force is the radial cutting force Fy in hard machining among three. The second deformation zone shows higher temperature. During the hard machining process, the tensile and compressive stress alternate on the surface of the workpiece. Finally, the surface of the workpiece presents compressive stress. 