Abstract:The single factor and orthogonal experimental reaserchs were carried out on the high speed milling of PAC5000 die steel. The regression mathematics models for milling forces, surface roughness and residual stress were established, and the influence degree of each milling parameters on test results was analyzed. The results show that the milling force, surface roughness will decrease with the increasing of the milling speed, and increase with feed pertooth, axial milling depth and radial milling depth increasing. The effects of various parameters on the axial milling force are all very big, axial depth of milling is the main influence factor of the axial milling force. The most sensitive effect of on parallel and perpendicular to the feed direction on the surface roughness respectively is feed pertooth and axial milling depth, the maximum effect is on perpendicular to the feed direction. The residual stress is shown as compressive stress on parallel to the feed milling direction, and the residual stress is shown as tensile stress on perpendicular to the feed milling directio, and improving the milling speed, which can reduce the residual stress.