Mo　alloying　Fe-based　coating　was　fabricated　on　the　surface　of　Q235　steel　by　using　6　kW　fiber　laser.　The　effects　of　Mo　additions　on　the　microstructure,　microhardness　and　wear　resistance　of　the　cladding　layer　were　studied　by　means　of　optical　microscopy　(OM),　scanning　electron　microscope　(SEM),　X-ray　diffraction　(XRD),　energy　dispersive　spectrometer　(EDS),　Vickers　hardness　tester　and　M-200　ring　block　wear　tester.　Research　results　showed　that　the　microstructure　of　Mo-free　cladding　layer　mainly　consisted　of　matrix　and　eutectic　structure.　The　matrix　was　martensite　and　retained　austenite.　The　eutectic　structure　mainly　consisted　of　M-2(B,C)　and　M-7(C,B)(3)　type　of　eutectic　borocarbides.　With　the　increase　of　Mo　content,　there　was　no　significant　change　in　the　matrix.　However,　the　eutectic　structure　was　transformed　from　M-2(B,C)-　and　M-7(C,B)(3)-type　borocarbides　into　M-2(B,C)-,　M-7(C,B)(3)-　and　M-23(C,B)(6)-type　borocarbides.　When　the　content　of　Mo　is　4.0　wt.%,　the　Mo2C-type　carbide　appear　on　the　matrix,　and　parts　of　the　borocarbide　networks　are　broken.　The　change　of　microhardness　of　the　cladding　layer　was　not　obvious　with　the　increase　of　Mo　content.　But　the　increase　of　Mo　content　increases　the　wear　resistance　of　the　cladding　layer.　The　wear　resistance　of　cladding　layer　with　4.0　wt.%　Mo　is　2.4　times　as　much　as　the　cladding　layer　which　is　Mo-free.