Objective　To provide anatomical basis for expanding the operation mode of lateral dorsal island flap.    Methods    The anatomic study was carried out on 33 sides of adult cadaveric lower limbs perfused with red latex. With the help of an operation microscope (×10 ) , anastomosis of the lateral dorsal artery and the lateral plantar artery was observed. Finally, we measured the location, diameter, length of the lateral foot vascular arch.    Results　The lateral dorsal artery and the lateral plantar artery had three constant anastomoses from the dorsal to the plantal aspect. The lateral tarsal artery issued a branch at the tuberosity of fifth metatarsal bone, which anastomoses with the lateral plantar artery and was named the first branch of lateral foot artery arch with an external diameter of (0.7±0.1) mm. Its occurrence rat was 54.5%. Two relatively constant anastomoses of the lateral calcaneal artery and the lateral plantar artery were named the second branch of the lateral foot arterial arch and the third branch of lateral foot arterial arch, respectively. The diameter was (0.9±0.1 ) mm and (1.0±0.2) mm，and the occurrence rate were 88.0% and 78.8%, respectively.   Conclusion   The lateral dorsal island flap pedicled with the lateral foot vascular arch is a nideal skin flap to repair the skin defects on the lateral plantar and  lateral calcaneus .