In order to analyze the interaction of laser and spherical particles in coaxial laser cladding, the physical model of laser scattering by spherical particles is established by using Mie scattering theory in certain assumptions, which will help select the laser and the spherical powder.The distributions of laser intensity with radius of particles and wavelength of laser were drawn by Mathematica software. The simulated results were analyzed. The results show the particles radius and laser wavelength are important parameters affecting the distribution of scattering intensity. There is a secondary maximum with direction deviation beyond 20° as the optical factor is less than 30. It accounts for a higher proportion of scattered light intensity, and it is adverse to the formation of molten pool. The scattering intensity is concentrated in the range from 5° to 6° as the optical factor is more than 30, and the scattering intensity is very strong in this range, which will promote laser cladding.