Abstract: Objective To study the effect of Lycium barbarum polysaccharides(LBP)on reproductive system damage induced by sub-chronic partial ⁶⁰Coγ-radiation in male rats.Methods Totally 84 Wistar male rats were randomly divided into 1 control group,3 radiation groups,and 3 LBP+radiation groups.After LBP gavage for 7 days,the treatment groups were exposed to ⁶⁰Coγ-ray local irradiation 5 days in a week for 4 weeks with the target distance of 80cm and the total dose of 2.3 Gy for each rat.The irradiation location was lower abdomen and the places above the anterior superior iliac crest was covered with 3 mm thick lead grid.During the irradiation,the rats in control group were administrated with equal quantity of normal saline.The rats in radiation groups and LBP+radiation groups were killed by severing the femoral artery at 1st,7th, and 14th day of the radiation and their sexual ability was observed and the sperm count and viability,the contents of superoxide dismutase(SOD)and malondialdehyde(MDA)were determined.Results The average mount of latency and ejaculation latency in radiation groups were 449.38 s and 463.25 s and significantly higher than those of the control group (272.75 s and 278.50 s)(P<0.01).Mount frequency,ejaculation frequency,and sperm count of the radiation group were also significantly different from those of the control group.SOD and MDA in model groups were 124.46 U/mg prot and 2.24 nmol/mg prot but those of the contorl group were 155.11 U/mg prot and 1.30 nmol/mg prot with significant differences(P<0.01).The mount latency and ejaculation latency in LBP+radiation groups reduced to 312.88 s and 325.00 s and the SOD activity and MDA content were 148.44 U/mg prot and 1.67 nmol/mg prot and similar to those of the control group.Conclusion LBP has obvious antagonistic effect on reproductive system damage induced by ⁶⁰Coγ-sub-chronic partial radiation and can promote the recovery of the damage in male rats.