Abstract: Effect of FeCrBSi Fe-based pre-alloyed powder (FeCrBSi) content by mass as sintering additive on sintering properties of 316L stainless steel (316L) by metal injection molding (MIM) was studied. The sintered density, metallurgical microstructures, and hardness of the sintered products were investigated by electronic densitometer, metallurgical microscope, and Rockwell hardometer, respectively. The results indicate that, the supersolidus liquid phase sintering is formed by FeCrBSi and 316L sintered at 1360℃, and the increase in liquid phase is beneficial to the sintering densification. The sintered density is increased with the rise of FeCrBSi mass fraction, and the porosity decreases in contrast. The sintered density is up to 7.81~7.87 g·cm^-3 when the FeCrBSi mass fraction is 3%~5%; whereas, the deformation is emerged when the FeCrBSi mass fraction increases to 7%. Hardness is improved with the increased relative density. The maximum hardness is reached as HRB 75, when the mass fraction of FeCrBSi is 3%, and the mechanical properties are also excellent at this time.