Objective : To investigate the effect of autophagy activation on cell proliferation in human umbilical vein endothelial cells (HUVECs) . Methods : HUVECs were treated with rapamycin (Rapa) . Western blot assay was performed to examine the expression of protein of microtubule associated protein 1 light chain 3 (LC3) , Beclin 1 and unc-51-like kinase 1 (ULK1) . Autophagosomes were detected by transmission electron microscopy ( TEM) , and autophagy fluorescence was detected by monodansylcadaverine staining(MDC) assay . The effect of autophagy activation on cell proliferation was assessed by CCK-8 assay and EdU assay . Vascular formation experiments were used to detect vasculogenic ability . Results : After Rapa treatment , LC3 , Beclin1 and ULK1 expressions were en- hanced , while the green autophagy fluorescence expression in the experimental group was stronger than that in the control group , and autophagosomes were visible by TEM ; CCK-8 and EdU results showed that compared with the control group , the cell proliferation ability was weakened and tubes formation ability was reduced after the activation of autophagy in experimental cells . Conclusion Rapa upregulates autophagy activity in HUVECs to inhibit cell proliferation under certain time .