Abstract: 15-5PH precipitation hardening stainless steel is a difficult material,so it will produce large cutting force and great plastic deformation during processing. Therefore, it is necessary to optimize its cutting parameters to optimize the cutting process. In this paper, the spindle speed, feed speed, axial cutting depth and radial cutting depth are taken as the optimization design variables, and the cutting force, surface roughness and material removal rate are taken as the response performance indicators. The response analysis model of high-speed milling precipitation hardening stainless steel is designed, and the response function analytical formula of the optimization design variables was analyzed and obtained. The influence of the interaction of various optimization design variables on the optimization objectives was studied. The optimal combination of reducing low cutting force and roughness and improving cutting efficiency for high-speed milling precipitation hardened stainless steel was obtained, which is v_c = 100 m/min, f_z = 0.02 mm/z, a_p=1.5 mm, a_e = 0.4 mm.