Effects of Cu85Sn15 intergranular additions on the magnetic and anti-corrosion properties of (Pr,Nd)12.6Dy0.9FebalB5.9 were investigated. Results showed that when 0.16 wt% Cu85Sn15 was added, the NdFeB magnet possessed the maixum values of the magnetic properties and anti-corrosion resistance. The improvement of corrosion resistance mainly arose from the increase in the density and from the optimized distribution of intergranular phases. Also the aforementioned optimization of structure factors benefited the anti-corrosion performance of NdFeB. Additionally, in the Cu85Sn15 doped magnet the occurrence of (Pr,Nd)6Fe13Cu and the decrease in the amount of (Pr, Nd)-rich phase reduced the formation of active reaction channels in the anodic intergranular regions, thus increasing the charge transfer resistance. As a result, the corrosion current density decreased and the corrosion resistance was enhanced.