Abstract: The changes of composition, microstructure and magnetic properties for the samples with composition of Pr₁₇Fe_76.5B₅Cu_1.5 cast alloys after hot-pressing with different strains to be 0%, 30%, 50%and 70% have been studied. As increasing of the strains, Pr and Cu contents of the smples decrease and Fe, B content of the samples increase, however the magnetic anisotropy and magnetic parameters such as μ₀M_s,B_r,iH_c,bH_c and (BH)_m of the samples enhance. The optimum magnetic properties of B_r=1.2 T, _iH_c=1.22 MA/m and (BH)_m=260 kJ/m³ for the samples with hot pressing strains to be more than 80% were obtained, which approaches to the magnetic properties of sintered Pr-Fe-B system magnets.