The samples with full density were prepared by hot pressing the the melt-spun powders mixed with DyF3 powders of different mass fractions followed by hot-deformation process.The magnetic properties and temperature dependence of coercivity were obtained by BH tracer and VSM,respectively.The microstructure were analyzed by scanning electron microscopy (SEM) and transmission electron mi-croscopy (TEM).The coercivity of Ce-containing hot-deformed magnets is increased from 1.41 to 1.95 T by grain boundary diffusion of 3 wt％ DyF3,and is further enhanced to 2.05 T after annealing treatment.The thermal stability of coercivity and remanence is improved.The annealing condition in this work crucially plays a role in thickening the grain boundary phase.Microstructure analysis reveals that the continuous and thick grain boundary phase formed after DyF3 diffusion can weaken the magnetic coupling between grains,and suppress the platelet shaped grain size and the aspect ratio.The Dy-containing shell structure formed by the partial diffusion of Dy into the main phase can increase the magnetic anisotropy field,which is the main reason for the coercivity improvement.After optimizing the structure by DyF3 diffusion,the “dendritic-like” reverse domain is transformed into the “dot scattered-like” reverse domain.