The application of Ni60A + WC coatings through laser cladding has been demonstrated to enhance the hardness, wear resistance, and corrosion resistance of the substrate. In order to achieve further enhancement in coating quality, the utilization of high-power laser cladding, with powers exceeding 2000 watts, has become a prevalent practice. Nevertheless, it is imperative to acknowledge that the augmentation in laser power can exert a profound influence on the surface morphology of the cladding layer. In order to investigate the formation mechanism of the uneven surface under high laser power, a heat flow coupling model was developed and orthogonal tests were conducted. The findings of this study suggest a positive correlation between surface unevenness and laser power, particularly at elevated scanning speeds. At elevated laser powers, the excessive rise in molten pool temperature enhances the fluidity of the molten metal, extends the retention time of the liquid metal, and induces inhomogeneous shrinkage during cooling. Additionally, an augmented temperature gradient at the molten pool surface intensifies the Marangoni effect, causing the molten metal to converge towards the edge of the laser spot, thereby reducing the surface quality of the molten cladding. The Marangoni force, which governs fluid flow at the surface of the melt pool, directs fluid away from the laser center, while buoyancy forces, which dominate at the bottom of the bath, push the fluid towards the laser center.