Laser cladding is favored in the fields of parts repair and coating preparation due to its significant advantages. The quality of laser cladding is affected by a number of process parameters, among which the laser power determines the heat input of the molten pool and directly affects the heat transport. In order to explore the influence of laser power on heat transport, a three-dimensional heat transport model of laser cladding is established, and the reliability of the model is experimentally verified, and the grid independence of the model is analytically demonstrated. The results show that under different laser powers, the time required for the molten pool to reach dynamic equilibrium is consistent, and the trend of temperature change in the molten pool is approximately the same. The peak temperature rises with the increase of laser power, and the peak temperature at 600 W is about 11% and 22% lower than that at 700 W and 800 W, respectively. The molten pool under the three powers has an annular flow mode from the inside to the outside, and the velocity of liquid metal increases with the increase of laser power.