Objective　To provide anatomic basis for clinic application of the first metacarpal artery retrograde island flap.    Methods    The origin, diameter, length and anastomosis of the first metacarpal artery were explored and observed in 58 sides of fixed adult cadaveric hand specimen. The origin and distribution of cutaneoud nerve related to the flap were observed. Arteriography was used in one side of a fresh adult hand specimen to observe the first metacarpal artery.    Results    The first metacarpal artery originated from snuffbox segment of radial artery, with the diameter and the length of（0.77±0.19）mm and (5.21±0.47)cm separately. The first metacarpal artery could be divided into three types: 35 sides(60%) were normal type, artery located at the radial side of the second metacarpal and anastomosed with the radial proper digital artery of index finger at second metacarpal cervix or radial side of the proximal phalanx of the index finger; 17 sides(29.2%) were variation type, and 6 sides(10.3%) were absence type. The first metacarpal artery accompanied with two veins(17 sides, 29%)，or with single vein( 11 sides, 19%）, or without vein(30 sides, 52%）.The sensory nerves of the flap area originated from superficial radial nerve.   Conclusions    Taken as the axis artery, the first metacarpal artery can be used to prepare reversed island flap to repair soft tissue defect in proximal thumb and index finger or dorsal metacarpophalangeal joint.