In this study, we developed a numerical model of the coaxial nozzle and powder transport process. Using numerical simulation we examined the effect of different processing parameters on powder convergence in the coaxial nozzle under both vertical and inclined conditions. Our results indicate that an increase in carrier gas velocity leads to a decrease in powder concentration at the powder focusing location, while the velocity of the shielding gas has little effect on the powder concentration. When the carrier gas velocity is 8 L/min, the shielding gas velocity is 20 L/min, and the powder feeding rate is 15.8 g/min, the use of the coaxial nozzle in an inclined position increases the focusing height of the powder from 19 mm to 21 mm and the focus diameter from 3.7 mm to 4.2 mm, compared to that in a vertical position. However, the uniformity of the powder distribution is much better when the coaxial nozzle is used vertically. Our numerical simulation results are consistent with the experimental results and can accurately reflect the powder transportation characteristics under different powder delivery methods.