Objective To explore the feasibility of building a new model of vascularized composite allotransplantation (VCA) of the knee in the rat. Methods Six Sprague Dawley rats were performed to anatomical study for understanding the vascular system of lower limb blood. According to the results of anatomical study, the animal model of vascularized knee allotransplantation was constructed by using super microscopy technique. The Sprague Dawley rat was used as recipients (n=12), Wistar rat (n=12) was used as the knee donors. The activities of animals were recorded with Lequesne MG in the postoperative. X-ray film was performed after transplantation at 4 weeks to reveal union at the bone junctions and the knee joint. Results The diameter of femoral artery in the deep femoral artery plane was [(0.94±0.11) mm]. Popliteal and saphenous vessels involved in the formation the peripheral vascular network of knee joint. When the femoral vessels were ligated in the distal of the deep femoral artery plane, it does not affect the blood supply of lower limbs in rats. According to the results of anatomical study, the animal model of knee joint allotransplantation was successfully performed based on the femoral vessel pedicle. Lequesne MG score was (6.50±0.79). X-ray film showed that the appeared of knee was grossly normal. Conclusion This study successfully constructed a kind of animal model of knee joint allotransplantation in rats. It can be used to provide a reliable experimental animal model for the study of vascularized composite allotransplantation. Key words: Vascularized composite allotransplantation; Knee; Model, animal