Boride layer was formed on the surface of Cr12MoV after being treated by boronizing technology, and it has high hardness, excellent high temperature oxidation resistance and other characteristics so the boronizing process are widely used in the heat treatment technology of mold and wear-resistant workpiece. But the boronizing technology also has disadvantages such as larger brittleness in the boronizing layer. In order to improve Cr12MoV boriding organizations, it is found that the infiltration of rare earth elements can improve the performance of a single boride layer. In this paper, by changing the temperature, time, rare earth addition and other parameters , the optimization parameter was obtained. and this could make infiltration layer more compact. The results of experiment also showed that the hardness and wear resistance of boride layer are significantly improved.