The structure and properties of powder RE-boronizing Layer are studied and compared with boronizing layer，It follows that RE-boronizing layer possesses higher wear-resistance, lower brittleness and finer stucture. It also shows that RE-atoms can be absorbed by the surface of steel, and migrate to the depth of 800μ with the aid of advanced analyzing methods. Besides, the mechanism of RE-boronizing and the effects of RE.