Objective To explore the promoting effect and its mechanism of shikonin on wound healing and neovascularization of rats with chronic skin ulcer. Methods Fifty of 60 male SD rats were selected to establish the rat model of chronic skin ulcer, of which 40 rats were done successfully and randomly divided into the model group, positive control group, and low- and high-dose shikonin groups (10 rats each). The other 10 rats served as the control group. The wound surfaces in low-and high-dose shikonin group were evenly smeared with 4 mg/cm² and 8 mg/cm² shikonin suspension, in positive control group with 1890 U/cm² recombinant bovine basic fibroblast growth factor gel to smear the wound, and in model group and positive control group were given the equal volume of normal saline for external application. The wound healing was observed on the 3rd,7th and 14th day of intervention. The abdominal aortic blood and wound granulation tissue of rats were taken after intervention, the histopathological changes of wound granulation were observed by HE staining, and the neovascularization was observed by immunohistochemical staining; the content of hydroxyproline (HyP) in granulation tissue was detected by hydrolysis method, the expression of Notch1 pathway related protein in granulation tissue was detected by Western blotting; and the levels of serum inflammatory factors were detected by ELISA. Results The wound healing rate of skin ulcer in each group increased with time and in a time-dependent manner (P<0.05). The wound healing rate decreased in low- and high-dose shikonin groups than in positive control group, and decreased in low-dose shikonin group than in high-dose shikonin group on the 3rd, 7th and 14th day of intervention (P<0.05). HE staining showed that new granulation tissue with a large number of inflammatory cell infiltration could be seen in model group. Compared with model group, old granulation tissue and inflammatory cell infiltration were observed in low- and high-dose shikonin groups and positive control group, and the inflammatory cell infiltration decreased in turn. Compared with that in positive control group, the IOD value of wound granulation tissue decreased in low- and high-dose shikonin groups(104 725.45±2062.45 vs. 197 585.23±2478.42, P<0.05; 149 752.54±2441.86 vs. 197 585.23±2478.42, P<0.05), and the content of HyP decreased [(3.62±0.12) μg/mg vs. (6.48±0.14) μg/mg, P<0.05; (4.94±0.15) μg/mg vs. (6.48±0.14) μg/mg, P<0.05].The IOD value and HyP content of wound granulation tissue were higher in high-dose shikonin group than in low-dose shikonin group (P<0.05). Western blotting results showed that the relative expressions of vascular endothelial growth factor (VEGF) and transforming growth factor β₁ (TGF-β₁) in wound granulation tissue increased, and of Notch1 protein decreased in low- and high-dose shikonin groups than in model group (P<0.05), while the relative expression of VEGF and TGF-β₁ increased and of Notch1 protein decreased in wound granulation tissue of high-dose shikonin group than in low-dose shikonin group (P<0.05). ELISA results showed that the levels of serum IL-8 and TNF-α decreased in positive control group and low- and high-dose shikonin groups than in model group (P<0.05), but increased in low- and high-dose shikonin groups than in positive control group (P<0.05), and decreased in the high-dose shikonin group than in low-dose shikonin group (P<0.05). Conclusion Shikonin may promote the wound healing and neovascularization of rats with chronic skin ulcer by regulating Notch1 signaling pathway.