In this study, factors affecting average shot velocity in the SMAT process were investigated numerically. The numerical model was developed by using the finite element method. The effects of frequency, amplitude, and projection distance parameters on shot velocity were simulated. Response Surface Methodology was used to evaluate the simulation results. ANOVA tables were used for statistical evaluation. Moreover, the regression equations derived from simulation results were compared with the theoretical equations. Besides, the effect of the amount of shot in the SMAT chamber on the velocity of the shot is simulated. The results showed that apart from frequency and amplitude, projection distance also had a significant impact on shot velocity.