Abstract: Mircostructures and properties of Re Pack boriding for 45 steel in low temperature are studied.The result shows that the decompounding temperature of Re is affected by the amounts and varieties of activation matter in the energizer.Re enhances the boriding rate greatly for 45 Steel in low temperature and total diffusion layer is provided with good homogeneity of the structure by increasing the boriding temperature.Moreover,suitable amount of Re can improve the wear resistance of boriding layer apparently.