【Abstract】 Objective To compare the effects of plateletrich plasma (PRP), alprostadil injection and combined use on ischemic skin flap in rabbits. Methods 40 rabbits were selected as experimental subjects, and randomly divided into 20 groups by statistical method, with 2 flaps in each group. Two flaps with the size of 10 cm*2.5cm and the ratio of super length to width were designed on the back of each rabbit, which were symmetrical in the midline, to form 4 rabbit dorsal ischemic skin flap models in each group. Each group was randomly divided into control flaps and experimental flaps. The control flaps were injected with local injection and normal saline intravenously. The experimental flaps were treated as follows: PRP was injected locally, saline was injected intravenously; Local injection of normal saline, alprostadil injection (0.8mL/kg) intravenously; Local injection of PRP, alprostadil injection (0.8mL/kg) intravenously. 7 days after the operation, take photographs and samples under the uniform standard. The survival area of each flap was measured and the survival rate of the flap was calculated. After HE staining, the tissue structure, inflammatory cell infiltration and microvascular diameter of each flap were observed under the microscope. CD34 expression was detected by immunohistochemistry and microvascular density was measured. The content of vascular endothelial growth factor (VEGF) was determined by enzymelinked immunosorbent assay(ELISA). Results On day 7 after the operation, different degrees of necrosis occurred at the distal end of each flap, and the average survival area, survival rate, microvascular density, and VEGF contents of each flap were in descending order : experimental flap 3＞1＞2＞control flap, and the difference was statistically significant (P＜0.05). The microscopic observation after HE staining showed that the edema of all experimental flaps was less than that of the control flaps, the number of new blood vessels was more, and the infiltration of inflammatory cells was less. Conclusion Both plateletrich plasma and alprostadil injection can improve rabbit ischemic skin flap vascular necrosis to varying degrees when used alone, and increase the survival rate of flaps, and the combined effect of the two is better than that of single use.