The　effects　of　chromium　content　on　microstructure,　hardness　and　wear　resistance　of　as-cast　Fe-xCr-1.0B　(x　=　0,　4,　8,　12,　16,　20)　alloys　were　investigated　by　means　of　optical　microscope　(OM),　scanning　electron　microscope　(SEM),　x-ray　diffractometer　(XRD),　hardness　tester　and　ring　block　wear　tester.　The　results　showed　that　the　microstructures　of　chromium-free　alloy　were　mainly　composed　of　pearlite,　ferrite,　and　eutectic　borocarbides,　and　the　hardness　was　very　low,　only　18.8　HRC.　With　the　increase　in　chromium　content,　the　matrix　of　as-cast　Fe-Cr-B　alloy　gradually　began　to　transform　from　pearlite　and　ferrite　to　lath　martensite,　and　the　type　of　borocarbides　changed　from　Fe-2(B,　C)　to　M-2(B,　C),　M-7(C,　B)(3)　and　M-23(C,　B)(6)　(M　=　Fe,　Cr).　When　the　chromium　content　was　12　wt.%,　the　hardness　of　alloy　reached　the　highest　value　of　61.1　HRC,　and　the　wear　resistance　of　alloy　was　the　best.　The　results　of　worn　surface　analysis　showed　that　the　wear　failure　of　as-cast　Fe-Cr-B　alloy　was　mainly　caused　by　multiple　plastic　deformation　and　micro-cutting.