Abstract: High-quality metallic powders are essential for the selective laser melting (SLM) technology. The powder characteristics are indispensible for the understanding of SLM technology. The influences of powder physical and chemical characteristics on SLM processing, component microstructure, and mechanical properties were reviewed in this work. For the physical properties, the powder morphology and powder size distribution could significantly influence the powder flowability and powder-bed packing density, which were vital for the subsequent laser melting. On the other hand, the chemical compositions, especially the contents of impurities, determined the phase constitutes and microstructures. Furthermore, the recent progress on the interaction between laser and powder and the corresponding metallurgical mechanism were also introduced.