A numerical simulation model of laser cladding based on internal powder feeding through a hollow laser beam is set up by Ansys parametric design language (APDL). The laser beam of cladding is a continuous motion ring form according to the process method of "hollow laser beam and internal powder feeding". Temperature distribution of laser cladding process can be got by model calculation. The calculation results show that, when the hollow laser beam is used, the highest temperature area of the molten pool is the saddle-shaped. In the base plate longitudinal section, the distribution of molten pool high temperature is asymmetrical "W" shape, and high temperature area mainly distributes behind the flare center. In base plate cross section, the distribution of molten pool high temperature is symmetrical "W" shape, the temperature of the molten pool center is low, and the both side temperature of the molten pool is high, thus the combination between cladding layer and base plate can be judged by the isothermal diagram. The temperature in the center of laser scanning undergoes twice sharp quenching and snap heat processes. It goes up and down rapidly first, and then goes up and down again. The second rising temperature is higher than the first one during the scanning. The temperature on both edges of the scanning tracks has only once sharp quenching and snap heat process, and the distribution of temperature is more uniform.