Objective To study the heating process of particles in plasma spray and influence factors. Methods The heating process and state of particles in plasma spray was calculated by Fluent software. Then the effect of standoff distance, diameter and materials of particles on the heating condition and temperature gradient of particles was analyzed based on the calculation results. Results During the heating process of particles under different standoff distances, the surface temperature of particles was higher than the center temperature of particles. In the cooling process, the center temperature was lower than the surface temperature and the surface-center temperature difference was far less than that in the heating process. There were different heating stages in heating process. For different diameters of particle, small particles could obtain better heating than the bigger one, although the bigger one could enter a deeper position in the center than the smaller one. The surface-center temperature difference increased with the raising of particle diameter. And particles with three different diameters had the similar tendency of the surface-center temperature difference. In regard to different materials, the materials with lower thermal conductivity had higher surface-center temperature difference, thus that would be harder for melting of particles completely. Conclusion Heating condition and temperature gradient of particles are sharply influenced by standoff distance, diameter of particles and materials of particles. And this simulation results can provide reference for the analysis of heat transfer between particles and plasma.