Objective: Astragalus mongholicus could promote angiogenesis.Microemulsion has been widely used in the researches of traditional Chinese medicine in recent years.This study aimed to investigate the effect of Astragalus mongholicus microemulsion modified-collagen on angiogenesis of rats in vivo.Methods: Fifty SD rats were randomly divided into 5 groups: blank collagen,blank microemulsion modified-collagen,vascular endothelial cell growth factor(VEGF) modified-collagen,Astragalus mongholicus microemulsion modified-collagen and Astragalus mongholicus microemulsion plus VEGF modified-collagen.Then four collagen samples were imbedded in each rat.After the establishment of the models,the rats were executed at 3,7 and 14 days.The weights of the collagen samples were measured,and their hematoglobin and hydroxyproline levels were determined by the hemiglobincyanide colorimetric and sampler alkaline hydrolysis methods.The color of the wound surface was observed and the surrounding tissues were examined by HE staining for those killed at 14 days.Results: Both Astragalus mongholicus microemulsion and Astragalus mongholicus microemulsion plus VEGF significantly increased the production of hematoglobin and hydroxyproline(P0.05).Conclusion: Astragalus mongholicus microemulsion might promote angiogenesis by increasing the number of micrangia and the production of hematoglobin and hydroxyproline.