The　effects　of　quenching　temperature　on　microstructure　and　performance　of　Al-bearing　cast　boron　steel　(ACBS)　containing　0.25-0.45%C,　1.5-1.8%B　and　1.4-1.6%Al　were　investigated　by　means　of　the　optical　microscopy　(OM),　the　scanning　electron　microscopy　(SEM),　X-ray　diffraction　(XRD),　Rockwell　hardness　and　Vickers　micro-hardness　tester.　The　results　show　that　the　solidification　structures　of　cast　steel　consist　of　high　hardness　boride,　ferrite,　pearlite　and　a　small　quantity　of　martensite　when　1.5-1.8%B　and　1.4-1.6%Al　are　added　into　the　carbon　steel.　The　metallic　matrix　of　ACBS　changes　into　single　martensite　from　the　mixed　structure　of　ferrite,　pearlite　and　martensite　along　with　the　increase　of　quenching　temperature.　The　increase　of　quenching　temperature　also　leads　to　the　transformation　of　boride　from　continuous　shape　to　isolated　shape.　Moreover,　the　micro-hardness　of　matrix　and　macroscopical　hardness　increase　with　the　increase　of　quenching　temperature.　When　the　quenching　temperature　excels　1000　degrees　C,　the　hardness　has　a　slight　decrease.　ACBS　has　good　comprehensive　properties　after　heat　treatment　at　1000　degrees　C.