The magnetization reversal processes of hydrogenation–disproportionation–desorption–recombination (HDDR) anisotropic Pr–Fe–B magnetic powders were systematically investigated. It is found that with the increase of external magnetic field, the magnetization first increases rapidly, and then increases slowly, and finally increases rapidly again. The increasing trend of coercivity with the increase of external magnetic field is just opposite to that mentioned above. Further micromagnetic simulation studies suggest that the coercivity is mainly controlled by the nucleation of reversed domain, and this is also indicated by the subsequent investigation for the evolution of the magnetic domain under the magnetic field.