To enhance the properties of hard alloy, rare-earth metal yttrium (Y) was implanted into its surface by using Metal Vapor Vacuum Arc(MEVVA) source implantor. The experiments were finished under different vacuum conditions with/without aerating nitrogen in the chamber. The metallograph and phase formation of sample were characterized and analyzed with metallurgical microscope and X-ray diffraction. The results show that there exist new phases of C, YC2, Y2O3, and WN in the sample surface. Moreover, it can be found that the performances of sample surface (such as microhardness, friction coefficient and corrosion resistance) are evidently improved, and that nitrogen atmosphere plays a very important role in farther promoting these performances. The surface modification of hard alloy is not only affected by the implantation itself, but also related to the microstructure transformation, which can be partly induced by the atmosphere. (C) 2011 Elsevier B.V. All rights reserved.