Abstract: TiAlN coatings were deposited on 304 stainless steel using Ti50Al50 alloy target by arc ion plating. Three kinds of rounded shielded plates with diameters of 80 mm, 100 mm, 120 mm were applied in arc ion plating system, which were placed in the meddle position between the target and the substrate frame. The coatings with shield plate were in comparison with the one without a plate. The composition and microstructure of coatings were characterized by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Their mechanical and tribological properties were determined by a microhardness tester, scratch and wear experiments. The results show that Ti content reduced while Al content in the TiAlN coatings increased with the increase of shielded plate size. The number of macroparticles on the surface and deposition rate decreased obviously. Increased the size of shielded plate decreased significantly the hardness and the adhesion strength of TiAlN coating. Friction coefficient and wear resistance of TiAlN coating with shielded plate were higher than that of the coating without shielded plate due to the formation of different kinds of pits.