Abstract: Objective: To invstigate the effects of different concentrations of the Xiangdan injection on the survival length of skin flap.Methods: Fifteen rabbits were randomly divided into 5 groups(group A,B,C,D and E),which were made a 16 cm 2 cm skin flap at back of rabbit, then the skin flap was in situ transplanted.Group A,B,C and D were given Xiangdan injection of 4 mlkgP＜/i＞-1P＜/i＞dP＜/i＞-1P＜/i＞with the concentration of 6%, 12%, 24%, and 48% respectively after operation,while group E was given normal saline as control.The skin flap survival status were recorded and the pathological changes were observed by HE stain in two weeks after operation.Results: The length of skin flat survival of group B and C were longer than that of group A,D and E(P＜0.01), and that of group E was the shortest.More fibrous proliferation and little tissue necrosis were found in group B and C, little fibrous proliferation and more tissue necrosis in group A and little fibrous proliferation and most tissue necrosis in group D and E under microscope.Conclusions: The 12%-24%concentrations of Xiangdan injection can improve the random skin flap survival.