CrN/ta-C　composite　coating　on　a　high-speed　steel　substrate　is　performed　by　magnetic　filtered　cathodic　arc　technique　and　magnetron　sputtering　technique.　Adheision　of　ta-C　film　on　the　high-speed　steel　substrate　is　studied　by　changing　the　preparation　process　of　a　buffer　layer　of　CrN.　The　results　are　as　follows.　With　the　increase　of　nitrogen　flow,　the　buffer　layer　chromium　nitride　experiences　the　phase　transition　of　Cr-Cr2N-CrN;　the　adhesion　of　the　coating　is　improved　with　the　increase　of　nitrogen　flow,　but　when　the　nitrogen　flow　exceeds　30　sccm,　the　adhesion　of　coating　will　decline;　the　preferred　orientation　and　grain　structure　of　chromium　nitride　are　changed　by　adjusting　the　substrate　bias;　the　adhesion　of　the　coating　is　improved　with　the　increases　of　the　bias　voltage,　but　when　the　bias　voltage　exceeds　200　V,　the　the　coating　adhesion　characteristics　will　be　slightly　reduced.　The　abrasion　resistance　of　the　test　also　shows　that　CrN　coating　can　significantly　improve　the　adhesion　of　the　ta-C　film　on　a　substrate　of　high　speed　steel,　and　can　also　significantly　improve　the　wear　characteristics.