In　this　paper,　the　effects　of　different　quenching　temperatures　on　the　microstructure,　hardness,　and　wear　resistance　of　modified　Al-bearing　high　boron　high　speed　steel　were　investigated　by　means　of　optical　microscopy　(OM),　scanning　electron　microscopy　(SEM),　X-ray　diffraction　(XRD),　a　hardness　tester,　and　an　MM-200　block-on-ring　wear　testing　machine.　The　results　showed　that　the　as-cast　microstructure　of　modified　Al-bearing　high　boron　high　speed　steel　consisted　of　martensite,　ferrite,　pearlite　and　continuous　network　eutectic　borocarbides　which　were　distributed　at　the　grain　boundary.　The　eutectic　borocarbides　mainly　included　M2B　and　M-7(C,　B)(3).　With　an　increase　of　quenching　temperature,　the　matrix　turned　into　martensite,　and　the　continuous　network　structure　of　eutectic　borocarbides　were　gradually　broken　and　changed　to　the　spherical;　the　secondary　borocarbides　M-23(C,　B)(6)　were　precipitated　from　the　matrix.　After　quenching　at　1150　degrees　C,　eutectic　borocarbides　were　clearly　visible　as　a　broken　network　and　spheroidal　in　shape,　and　the　distribution　was　more　uniform.　When　the　quenching　temperature　was　in　a　range　of　1000　degrees　C　to　1150　degrees　C,　the　hardness　and　wear　resistance　of　the　alloy　obviously　increased.　When　the　quenching　temperature　attained　1150　degrees　C,　hardness　reached　the　highest　64.3　HRC,　and　the　wear　resistance　was　best.