Using the are ion plating(AIP) process, TiN coating was deposited onto high speed steel substrates. The effects of coating thickness, titanisum interlayer and shield on wear resisting capability of the coated tools were investigated. In order to promote good adhesion between the substrate and the TiN coating a thin Ti interlayer was deposited. A shield was set up also between Ti target and high speed steel substrates to prevent molten droplets from reaching the substrate. Three series of varying thickness of TiN coated layer were prepared with or without the Ti interlayer, and with or without the shield. The tools with the Ti layer and the shield showed longer tool lifes than those of other series of tools and the commercially available TiN coated HSS tools, by up to 70%.