Particle impingement velocity is one of the most important parameters in solid particle erosion. Particle impingement velocity depends on erosion test parameters such as particle acceleration pressure, erodent particle size and standoff distance. Over the past decades many experimental studies have been conducted to examine the effects of these parameters on the particle impingement velocity. In this study, the effects of particle acceleration pressure, erodent particle size and standoff distance on the particle impingement velocity have been investigated by using a computational fluid dynamics (CFD) program, FLUENT. In order to achieve these goals solid particle erosion tests are simulated under various test parameters and the effects of these parameters are examined in detail. The effect of particle velocity on the flow field is characterized with method geometrics. Two-dimensional plane symmetrical models are utilized to reduce the computation time. Plots of gas pressure and particle velocity contours at the XY symmetrical plane from nozzle inlet to substrate were given. CFD analysis showed that all erosion test parameters have dramatically affected particle impingement velocity. Particle impingement velocity was increased with increases in acceleration pressure while it was decreased with increases in both erodent particle size and standoff distance.