Authors analysed 36 cases(33 patients) of Peroneal Buoy Flap to investigate branching pattern, course, length of vascular pedicle, and perforating level of the perforating cutaneous branches from Oct. 1985 to July 1988. The results were as follows. 1. The perforating cutaneous branchea were classified into four types, the Straight Branch (18 cases), the Proximal Oblique Branch (8 cases), the Branch from Muscular Artery (8 cases), the Distal Oblique Branch(2 cases) respectively. The most common patten was Straight Branch. 2. There were 3 pathways of these branches, the most common one passed between the Soleus and Peroneus muscles(23 cases, 64%), and second one passed through the snterior part of Soleus muscle(8 cases, 22%), the third one passed through the posterior part of Peroneus muscle(5 cases, 14%). 3. The length of vascular pedicle in Buoy Flap was variable from 3cm to 15cm, but 27 cases(75%) were distributed between 4cm and 6cm. 4. The perforating level of branches were 6.3cm in average from Fibular Neck, 88% of them were distributed within 10cm. 5. Peroneal Buoy Flap in possible to reconstruct both seperated bone and skin defect in some distance by One-Stage Operation.