Abstract: The irregular-shaped hydrogenation-dehydrogenation (HDH) Nb521 alloy powders were modified by fluidization to improve the sphericity and flowability in this study. The fluidized Nb521 powders basically met the requirements of 3D printing. The powder morphology, particle size distribution, interstitial element content, sphericity, and flowability were characterized and analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), particle size analysis, and chemical analysis. The results show that, the particle size distribution of the irregular-shaped HDH Nb521 alloy powders becomes narrow after the fluidization, the sphericity and flowability are significantly improved, while the impurity level is effectively controlled. The spreading performance of the fluidized Nb521 powders during 3D printing exhibits quite well.