Ni coated WC is cladded on 42 CrMo alloy surface by using IPG YLS-6000 high power fiber laser, and the effects of laser power on microstructure and properties of Ni coated WC coating are studied. It is found that with the increase of laser power, the microstructure shows a trend of roughening, and the coating hardness decreases because of WC particles gradually decompostion into Fe-C compounds. Also, when the laser power is 1 800 W, micro hardness is 1 050 HV. Furthermore, the wear resistance of specimens is significantly improved by laser cladding. Under the same wear condition, the abrasion loss of coating is only about 1/5 of the substrate. And the influence of laser power on the coating wear is not obvious.