Laser solid forming (LSF) is a promising manufacturing technology. During LSF process, powder flow plays an important role in the formation of deposition layer. A turbulent flow model is build, and based on the analysis of the movement of particles in the turbulent flow, a powder flow model is developed by the numerical method and solved by using the Fluent software, so the powder mass concentration of the powder flow can be obtained. Comparisons between the simulations and the experimental results are carried out. It is found that the simulations of the powder flow agree well with the experimental measurements. The powder mass concentrations have a few obvious differences with the change of particle diameter range, as proved by the simulation results of particle diameters of 50~240 μm and 65~75 μm.