Objective To study the antifatigue effect of hempseed fermented liquid. Methods 100 Kunming mice were randomly divided into five groups a control group, low dose and high dose hempseed protein groups and low dose and high dose fermented liquid groups [1.3 g/(kg·d) and 2.6 g/(kg·d)],which were given distilled water and the corresponding drugs via gastrogavage. The mice were gavaged one time a day,and continued for 30 days. Thirty days later,the exhaustive swimming time in the mice were recorded, and the indexes of lactic acid levels were tested and analyzed. Results Compared with the hempseed pretein group,different doses of hempseed fermented liquid could prolong exhaustive swimming time significantly(P＜0.05),and decrease accumulation of lactic acid significantly in the blood(P＜0.05). Conclustion Hempseed fermented liquid has obviouse antifatigue effect.