The research object were additive manufacturing GH3625 metal powders,the two-dimensional microstructure of the powders were observed by scanning electron microscopy(SEM), the three-dimensional structure of the powders were characterized by micro-CT,and the geometric parameters such as particle size, volume and sphericity of the powders were quantitatively analyzed. All the pores inside the hollow powders were successfully extracted by three-dimensional(3D) segmentation, and the 3D printed powder quality was characterized by volume porosity, probability of hollow powder, sphericity and other parameters.Finally, the influence of the pore diameter in the hollow powder on the sphericity of powders were investigated. The experimental results show that micro-CT is an ideal tool to characterize the quality of metal powders of additive manufacturing, a total of 20576 GH3625 powder particles were detected by CT, the average particle diameter of the powder is 28.16 μm, the number of hollow powder particles is 1440,the number of internal pores is 1515, and a few powder particles have multiple pores,it is found that the sphericity of the hollow powder particles decreases with the increase of the internal pore diameter of the hollow powders.