Abstract: Objective The model of acute ischemic-reperfusion injury in the lower limbs of rats was established.The effect of clamping the femoral artery time on the injury model was explored.The appropriate clipping time was used to establish the model. Methods Forty SD rats were randomly divided into 5 groups,8 rats in each group,including blank control group（Control group）,sham operation group（Sham group）,ischemia-reperfusion group（I/R group）;The reperfusion group was divided into a 3-hour group（IR3）,a 4-hour group（IR4）,and a 5-hour group（IR5）according to the clipped femoral artery.After anesthesia in rats,the left hind limb of the rat was freed from the femoral artery and vein.The femoral artery was clamped with a microvascular clamp,and the femoral artery and vein were ligated by suture.After 3,4,and 5 hours of clamping,blood perfusion was resumed for 2 hours.The rubber band was used to elastically circumscribe the hind limbs under the blood vessel clamp,and the collateral circulation was blocked.The Sham group only exposed the femoral triangle and did not ligature the arteries and veins and their branches.Each group of animals took blood at 0,2,4,and 8 hours after the end of the clipping.After the end of perfusion,the rat gastrocnemius muscle was taken.At the end of the test,the levels of CK and LDH in the serum were measured,and the levels of MDA and MPO in the gastrocnemius muscle were detected. Results After testing,the rats in the lower extremity ischemia and reperfusion,MDA、MPO、CK、LDH of the blood related indicators and MDA、MPO of muscle tissue related indicators have caused varying degrees of damage. Conclusions The longer the ligation time,the more severe the ischemia-reperfusion injury in rats,and the time required for recovery will gradually increase or even recover.After comparison,it is reasonable to choose a ligation time of 4 hours.