The purpose of the present study was to investigate the effects of Lycium barbarum polysaccharides (LBP) on exercise-induced oxidative stress in rats. Rats were divided into four groups, i.e., one control group and three LBP treated groups. The animals received an oral administration of physiological saline or LBP (100, 200 and 400 mg/kg body weight) for 28 days. On the day of the exercise test, rats were required to run to exhaustion on the treadmill. Body weight, endurance time, malondialdehyde (MDA), super oxide dismutase (SOD) and glutathione peroxidase (GPX) level of rats were measured. The results showed that the body weight of rats in LBP treated groups were not significantly different from that in the normal control group before and after the experiment (P > 0.05). After exhaustive exercise, the mean endurance time of treadmill running to exhaustion of rats in LBP treated groups were significantly prolonged compared with that in the normal control group. MDA levels of rats in LBP treated groups were significantly decreased compared with that in the normal control group (P < 0.05). SOD and GPX levels of rats in LBP treated groups were significantly increased compared with that in the normal control group (P < 0.05). Together, these results indicate that LBP was effective in preventing oxidative stress after exhaustive exercise.