The particle impact behavior of Stellite 6 on steel substrate in the supersonic laser deposition (SLD) process is studied using numerical simulation, compared with experimental data. The impact characteristics of Stellite 6 are analyzed with respect to particle size and deposition temperature. The simulation results show that laser deposition temperature of 1000 °C for the substrate is the optimal in terms of the interface bonding between the particles and substrate. The particle size of 40 μm exhibits the best deposition interface. The simulation results agree well with the experimental measurements. The depths of impact indentation with different particle sizes and at different temperatures are investigated to obtain the relationships between process parameters such as particle diameter, indentation depth, and deposition temperature. To further understand the effects of collisional behavior of multi-particles on the stress-strain distributions and the micro-zone in the particle and substrate system, different micro-zones of the impact particle are analyzed; the variations of the stress and strain with time for the substrate and particle are obtained from the simulation results. The impact characteristics of Stellite 6 deposited on steel substrate are discussed.