Abstract:mold spray plays an important role in pressing process. This paper studies the effect of different mold spray on the properties of the magnet with different carbon content. The results show that with the increase of carbon content, NdFeB magnet coercivity and corrosion resistance decreased.but the effect of remanence and energy product is not obvious. The reasons for decline of intrinsic coercivity and corrosion resistance due to exists of carbon in the Nd rich phase, which cause damage to the Nd rich in part.