Abstract: Three bovine breeds,including Chinese holstein, Sanhe cattle and Chinese simmental were used as experimental examples.T/G，G/A and G/A polymorphic sites which can be cut by EcoRⅤ，HaeⅢ and HhaⅠrestriction enzymes were genotyped by PCR-RFLP and CRS-RFLP analysis，T/G polymorphic sites cause the D/E AA variation.A chi-square analysis suggested that the three bovine breeds reached Hardy-Weinberg equilibrium in the three polymorphic sites ( P > 0.05). Chinese simmental has the highest polymorphism in the three bovine breeds. The associations were observed between genotypes and SCS traits at HaeⅢ and HhaⅠrestriction enzymes polymorphic sites in three bovine breeds ( P > 0.05),meanwhile EcoRⅤ restriction enzyme polymorphic site( P< 0.05). The results of least squares means showed that a significant different effect between genotype BB and AB or AA was found in EcoRⅤ restriction enzymes polymorphic site ( P< 0.05) ,The BB genotype of the EcoRⅤ restriction enzyme polymorphic site would be the best genotype to resist mastitis.