Abstract: Protective effects of Lycium Barbarum polysaccharides (LBP) on diethylstilbestrol (DES) induced oxidative damage in hamster testis was studied in this experiment. Adult hamsters (Mesocricetus auratus) were randomly divided into 4 groups: Control group, DES group, DES+LBP group, DES+V_C+V_E group. Absolute and relative testicular weight were calculated, morphological changes of testis were observed and the contents of SOD, GSH-Px, T-AOC, MDA in testis tissue and plasma were detected after 7 successive days treatment. The results showed that LBP had an evident effect in reversing the reproductive damage induced by DES. In DES+LBP group, the absolute and relative testicular weight were significantly upgraded (P <0.05) and the seminiferous tubules were lined up in order. Levels of SOD and TAOC elevated markedly in LBP group (P <0.01),which was similar with control, but MDA showed the reverse tendency. There was no significant difference between LBP and vitamin group. It is concluded that LBP could efficiently restrain the production of reactive oxygen species, inhibit the generation of lipid peroxidation, accordingly attenuate the reproductive toxicity of DES. These results indicated that LBP is one of the active components in attenuating the oxidative damage induced by environmental estrogens.