The milling experiments of the annealed T10A steel were carried out in the various cutting conditions using the coated cemented carbide tool. The cutting parameters were designed by the multi-factor orthogonal experiment method, and the effects of cutting speed, feed, axial depth of cut and radial depth of cut on the cutting force and tool wear were investigated. The tool wear mechanisms were also discussed. Adhesion, abrasion, diffusion and oxidation were the main tool wear mechanisms. According to these investigations, the optimizing cutting parameter was recommended.