Oat protein was purified from oat meal and its effects on swimming performance and related biochemical parameters were investigated. Thirty male Kun-ming mice were divided into the normal control, the oat meal and the oat protein group (n = 10). They were fed with a laboratory food for 30 days, then were subjected to swim to exhaustion. Their swimming endurance and the major metabolic substrates were measured from serum, liver and muscle. The results showed that no significant differences were observed in swimming endurance test between the normal control group and the oat protein group (P > 0.05). Mice in the oat meal group had significantly longer swimming endurance compared to the normal control group (P < 0.05). Furthermore, dietary oat protein increased the levels of liver glycogen, enhanced the activities of lactic dehydrogenase and superoxide dismutase, and decreased the levels of blood urea nitrogen and malondialdehyde in serum. These results suggested that oat protein was effective in improving the physiological condition of the mice.