To investigate the alleviating effect on physical fatigue of the %Polyhachis vicina Roger % (PVR), experiments were undertaken in mice. The effect of PVR extract on burden swimming, and biochemical indexes(liver starch content, serum LA content and serum urea-nitrogen content) were determined. Four groups of mice had been given PVR extract at different doses(0,0.036,0.358,1.074 g/kg BW) by gavage for 30 days. The results indicated that the PVR extract at different doses had effect of alleviating physical fatigue. The lower dose of the PVR extract remarkably prolonged the duration of swimming ( P <0.05), the higher dose increased the content of mice liver starch notably ( P <0.01).