The　NiCrMoAl/WC　composite　coatings　with　different　contents　of　WC　particles　were　deposited　on　P550　steel　by　laser　cladding.　The　microstructure　and　magnetic　properties　of　the　coatings　were　characterized　by　SEM,　EDS,　XRD　and　VSM.　The　magnetism　of　phases　was　calculated　by　the　first-principles　based　on　the　density　functional　theory.　The　results　show　that　the　coatings　are　mainly　composed　of　gamma-Ni,　WC,　W2C,　Ni2W4C,　Ni3Mo3C,　Mo2C　and　AI(4)C(3).　The　relative　permeability　of　the　coatings　increases　from　1.002　to　1.080　with　the　increase　of　WC　percentage　from　24　wt%　to　60　wt%.　The　phases　of　WC,　W2C,　Ni2W4C　and　Al2C3　are　non-magnetic,　Ni3Mo3C　and　Mo2C　are　weakly　magnetic　according　to　the　calculations.　The　weak　magnetism　of　Ni3Mo3C　originates　mainly　from　the　strongly　correlated　interaction　of　3d　electrons　in　Ni　atoms,　whereas　that　of　Mo2C　originates　mainly　from　the　d-state　electrons　of　Mo　atoms.　The　weak　magnetism　of　the　coatings　(WC　＞=　48　wt%)is　related　to　the　metallurgy　behaviors　of　WC　particles.　The　C　elements　resulting　from　the　decomposition　of　WC　particles　can　be　diffused　into　the　Ni-based　alloy,　thus　resulting　in　the　formation　of　weakly　magnetic　phases　in　the　cladding　layer,　such　as　Ni3Mo3C　and　Mo2C.