Garnet, the most widely used abrasive material in abrasive waterjet machining (AWJM), presents challenges in modeling its behavior. Therefore, a finite element (FE) model was proposed to analyze the effect of using different material models and spatial distributions for garnet on the erosion behavior of Al 7075-T6. Three popular material models were considered for garnet, including rigid, linear elastic, and tensile failure models, in addition to the Johnson-Holmquist (JH2) model. These four models were tested and compared for single and multiple particle impact under different waterjet pressures, abrasive mesh sizes, and impact angles. Furthermore, the effect of particle spatial distribution within the jet pass was examined. The model results demonstrated that using different material models for garnet significantly controls the erosion behavior in AWJM. In addition, the radial distribution of the abrasive particles critically affected the erosion process and kerf geometry, while the axial distribution insignificantly influenced the erosion rate.