Abstract: The austenitic stainless steel additive manufactured by laser powder bed fusion (LPBF) has a good application prospect because of its good printability and mechanical properties, but there are still some problems that limit its industrial application. Adding nano-reinforcing phases is one of the effective strategies for regulating the properties of LPBF austenitic stainless steel. The review summarized the research progress of nanoparticles-reinforced LPBF austenitic stainless steel. We focused on discussing the effect of nanoparticles on the densification, microstructure, and mechanical properties. The strengthening mechanism was analyzed. Due to the addition of nanoparticles, the porosity of the composite material increased, and the density decreased. Cellular structure grains were finer with low anisotropy. Austenitic stainless steel added reinforcement phase not only significantly improved strength but also maintains good plasticity, mainly attributed to the comprehensive effects of grain refinement, dislocation strengthening, Orowan strengthening, and load transfer strengthening. Finally, the research directions of nanoparticles reinforced austenitic stainless steel by LPBF that need to be further explored in the future were prospected.