In this experimental study, three sorts of grafts (venous flap, composite graft and axial flap) were created. According to the results of relative contents of LD1, and LD5 in these grafts, the conclusion was drawn: Oxyhemoglobin remaining in the grafts maintained normal carbohydrate metabolism within 24 hours postoperatively. 48 hours later, aerobic oxidation of carbohydrate abated but kept in a considerable level in venous flaps due to the existence of venous blood. 72 hours after the operation, aerobic oxidation of carbohydrate in venous flaps reached its lowest point. At this point, the venous flaps would necrose gradually unless a new nourishing source be obtained. From the 4th postoperative day, aerobic oxidation of carbohydrate of venous flaps began to increase. By the 7th day, aerobic oxidation of carbohydrate of venous flabs returned to normal.