To enhance the forming quality and mechanical properties of metal-based composite coatings, WC-Ni60AA composite coatings were prepared on the surface of 65Mn via laser cladding. The influence of Mo element addition on the forming quality, phases, microstructure, microhardness, and frictional wear of the coatings was systematically investigated. The wear mechanism of the composite coatings was analyzed in depth, with particular attention to the grain refinement mechanism and crack inhibition mechanism induced by Mo elements on the coatings. The results indicate that the coatings without Mo element exhibit numerous “Y-shaped” cracks on the surface, with dense cracks in the top part and sparse cracks in the bottom part, and the main crack deviates towards the laser scanning direction. Upon addition of Mo elements, the crack density of the coatings initially decreases and then increases, with complete elimination of coating cracks observed at an addition of 1.00 wt% Mo. Prior to Mo addition, the main phases in the coatings are γ-(Fe, Ni), Fe3W3C, W2C, and M23(C, B)6. After Mo addition, a new phase Mo2C appears in the coatings. The addition of Mo elements strengthens the grain boundaries of the coatings, refines the grains, and transforms the originally coarse cellular and dendritic structures into fine, dense equiaxed grains. The average hardness of the coatings initially decreases and then increases. The coating with 1.00 wt% Mo addition exhibits the highest average microhardness, minimal average friction coefficient, and wear rate, with the wear mechanism being abrasive wear and slight spalling wear. The oxide film formed by Cr2O3, NiO, and MoO3 in the coatings enhances the wear resistance of the coatings.