Skin flap have been developed recently for wide employment in plastic and reconstructive surgery due to advances in microsurgery. After microvascular free flap transfer, the vascular occlusion did not affect flap survival after neovascularization appears to perfuse the flap. But if the flap exclu-de the recipient bed and perimeter, the flap survival depended solely on the axial vessel. This model would enable a clinical assessment of the viability of tissue and the patency of microvascular anastomosis long after the anastomosis is performed. Reexploration would not be necessary. We designed the island flap included the recipient bed and perimeter and the tube flap excluded it in rats. We investigated that the time of neovascularization after the free flap transfer, the assessment of microvascular patency and the importance of the arterial inflow or venous drainage for flap survival. In results, neovascularization appeared to perfuse the flap 4 days after free flap transfer in the island flap. A venous capillary bed developed quickly in the flap bed whereas the arterial capillary bed, sufficient to adequately perfuse the flap, developed much slowly. Therefore, we suggest the possibility that the arterial in-flow in the flap is more important for the flap survival.