In order to study the process of revascularization of free flap bilateral dorsal-auricular free flaps of 18 Newzealand rabbits were completed and investigated with the technique of microvascular corrosion casting at 2,4,7,10 days and 2,4 weeks postoperatively.It was discovered that scarce neovascularity appeared around the margin of flap before 2 weeks following transplantation and extensive revascularization occured at 3 weeks postoperatively.The capillaries connected through their netword expansion while central artery and vein formed recirculation by means of multiple point anastomoses of the "vascular buds" sprouting up at both ends of vessels.