Objective:To investigate the effect of Astragalus mongholicus microemulsion modified-collagen on proliferation of human umbilical vascular endothelial cells(HUVEC) in vitro. Methods:Cell line of HUVEC was cultured and all experiments were performed using the cells at the third passage. After synchronization of cells growth,HUVEC was divided into blank microemulsion modified-collagen group and Astragalus mongholicus microemulsion modified-collagen group. Each group was exposed to the concentrations of 16.90,8.50,4.20,2.10 and 1.05 μg/ml,respectively. The proliferation of HUVEC was measured by MTT and flow cytometry assay. The real-time quantitative PCR was used to detect the expression of vascular endothelial cell growth factor(VEGF) mRNA in HUVEC. Results:After co-culturing for 48 h,the proliferation and VEGF mRNA expression of HUVEC in Astragalus mongholicus microemulsion modified-collagen group at the concentrations of 16.9,8.5 and 4.2 μg/ml significantly increased compared with the groups on the same concentrations in blank microemulsion modified-collagen control(P < 0.05,P < 0.01). Conclusion:Astragalus mongholicus microemulsion not only promotes the proliferation of HUVEC,but also upregulates the expression of VEGF mRNA. This study demonstrateds that Astragalus mongholicus microemulsion may promote angei-anagenesis.