The influence of Pr on thermal stability, microstructure, and magnetic properties of melt2spun (Nd1-x Prx) 10.5 (FeCoZr) 83.5B6 (x=0,0.2,0.4,0.6,0.8,1.0) alloy was investigated. By sub2overquenching to get the mixture of amorphous and fine crystallites and post annealing under the optimum conditions,bonded magnets with the best magnetic properties were prepared. With the increase of Pr content, Hci increases, but Br decreases. (BH) max of magnets bonded with 3.25 %(mass fraction) epoxy reaches the maximum of 7016 kJ•m-3 at x=0.6～0.8. Substitution of Pr for Nd causes the crystallization temperature and crystallization energy to decrease. This ther-mal stability difference results in that (Nd0.2Pr0.8) 10.5 (FeCoZr) 83.5B6 alloy has a rougher and more inhomogeneous microstructure than that of (Nd0.8Pr0.2) 10.5 (FeCoZr) 83.5B6 alloy, furthermore, leads to the decrease of B r with the increase of Pr content.