Laser　clad　Fe-Cr-B　alloy　coating　was　fabricated　on　the　surface　of　Cr12MoV　mold　steel　by　using　a　6　kW　fiber　laser.　The　effects　of　laser　power,　scanning　velocity,　powder　feeding　rate　on　the　formability,　size,　dilution　rate,　microstructure　and　microhardness　of　the　cladding　layer　were　researched　by　means　of　metallographic　microscope　and　microhardness　tester.　The　results　show　that　the　microstructure　of　the　cladding　layer　is　composed　mainly　of　plane　crystal,　dendrites　and　equiaxial　grains.　The　proper　laser　cladding　parameters　determined　based　on　the　experiment,　which　are　as　follows:　P　(laser　power)=2000　W,　V1(scanning　speed)=4　mm/s,　V2(powder　feed　rate)=15　g/min.　Under　the　laser　cladding　parameters,　the　fine　gains　are　obtained,　the　dilution　rate　is　9.8%　and　the　highest　microhardness　of　the　cladding　layer　exceeds　1000　HV.