The change rule of powder properties of SS316L stainless steel powder after recycling is studied,and the evolution mechanism of powder morphology and particle size distribution is clarified. The results show that as the number of powder cycles increases,the particle size distribution of the powder becomes narrow and coarser,the apparent density and tap density of the recycled powder are improved to a certain extent,and the flowability of the powder is also improved comparing with the original powder,but the change trend of Hausner’s ratio is opposite to that of Hall’s flow rate. The surface chemical components of recycled powder particles are oxidized severely,and the ellipsoidal oxidation spots and metal vapor condensate are found on the surface of powder particles. In this study,the irregular particles in the recycled powder are divided into two categories: the first is laser-induced molten pool spatter particles,the second is gas entrainment induced particles,and the formation mechanism of the two kinds of irregular particles is described respectively. The results of this study emphasize that in the recycling process of raw materials,the oxidation of powder and the generations of irregular particles are unavoidable.In the future,more consideration should be given to the effects of irregular particles,vapor condensates and oxide particles on the quality of the processed parts.