Laser cladding of nickel-based composite layer is much helpful to improve surface properties of H13 steel. WC/Ni60A composite powder with WC mass fractions of 20%, 33% and 50% is respectively cladded on the H13 steel surface. Based on optimized parameters of laser cladding process, the microstructure of the cladding layer is studied. The results show that the phase composition of the laser cladded WC/Ni60A composite layer is complex. WC content has a significant effect on the formation and morphology of the cladding layer structure. When the mass fraction of WC is 20%, the cladding layer is composed of much γ-(Fe, Ni) branch crystal and a small amount of Wrich carbide; when the mass fraction of WC is 33%, the cladding layer, with a special structure, is composed of a large amount of flocculent eutectic structures which are concentrated by M₂₃C₆ blocks and surrounded by eutectic structure composed of M₂₃C₆ and γ- (Fe, Ni); when the mass fraction of WC is 50% , much block- shaped M₆C, snowflake-shaped M₂₃C₆ and needle-like Cr₄Ni₁₅W structure is generated in the cladding layer. The hardness of the laser cladding layer increases remarkably compared with that of the substrate and is up to 730, 760, 810 HV, when the mass fraction of WC is 20%, 33% and 50%, respectively.