In　the　present　study,　the　microstructure　and　mechanical　properties　of　cast　Fe-10Cr-1.5B　(FCB)　alloy　after　different　heat　treatments　were　studied.　The　results　showed　that　the　as-cast　microstructure　of　FCB　alloy　consists　of　alpha-Fe,　M(M=Cr,　Fe,　Mn)(2)(B,　C)　and　M(M=Cr,　Fe,　Mn)(7)(C,　B)(3)　type　borocarbides,　and　small　amounts　of　pearlite　and　austenite.　After　oil　quenching　treatment,　metal　matrix　transformed　into　the　martensite　from　the　mixture　of　martensite,　pearlite　and　austenite.　There　are　many　M(M=Cr,　Fe,　Mn)(23)(C,B)(6)　type　borocarbide　precipitates　in　the　metal　matrix,　and　eutectic　borocarbide　appears　with　an　apparent　disconnection　and　isolated　phenomenon.　When　the　quenching　temperature　reaches　1,050　degrees　C,　the　hardness　of　FCB　alloy　is　the　highest,　but　the　change　of　quenching　temperature　has　no　obvious　effect　on　impact　toughness　of　FCB　alloy.　After　tempering,　the　eutectic　microstructure　of　FCB　alloy　appears　with　a　＂two　links＂　trend.　With　the　increase　of　tempering　temperature,　the　hardness　of　FCB　alloy　decreases　gradually　and　impact　toughness　increases　gradually.　Cast　FCB　alloy　oil-quenched　from　1,050　degrees　C　and　tempered　from　200　degrees　C　has　excellent　combined　properties;　its　hardness　and　impact　toughness　are　61.5　HRC　and　8.8　J.cm(-2)　respectively.