Abstract: The gate location in metal powder injection molding (MIM) significantly influences the uniformity of powder concentration distribution. This study addresses the powder-binder separation issue during the injection molding of stepped stainless steel parts by simulating filling processes for four different gate location schemes. By analyzing fluid flow direction, shear rate, and temperature field, the study reveals the influence patterns of gate location on powder concentration distribution. Results indicate that binder aggregation occurs near all gate positions. However, altering the initial flow direction of the feedstock by changing gate locations effectively mitigates powder concentration non-uniformity. For injection-molded parts exhibiting thickness gradients, the gate should be prioritized at the thick-walled end, employing a thick-end feeding approach. Opting for thin-end feeding may lead to cavitation collapse at the step transition and powder-binder separation issues. Additionally, the stepped structure of the part exacerbates powder segregation. These findings provide a basis for improving powder distribution and enhancing green compact quality, holding engineering significance for reducing part defect rates.