Acute coronary syndrome caused by the rupture of atherosclerotic plaques is one of the primary causes of cerebrovascular and cardiovascular events. Neovascularization within the plaque is closely associated with its stability. Long non-coding RNA (lncRNA) serves a crucial role in regulating vascular endothelial cells (VECs) proliferation and angiogenesis. In this study, we identified lncRNA HCG11, which is highly expressed in patients with vulnerable plaque compared with stable plaque. Then, functional experiments showed that HCG11 reversed high glucose-induced vascular endothelial injury through increased cell proliferation and tube formation. Meanwhile, vascular-related RNA-binding protein QKI5 was greatly activated. Luciferase reporter assays and RNA-binding protein immunoprecipitation (RIP) assays verified interaction between them. Interestingly, HCG11 can also positively regulated by QKI5. Bioinformatics analysis and luciferase reporter assays showed HCG11 can worked as a competing endogenous RNA by sponging miR-26b-5p, and QKI5 was speculated as the target of miR-26b-5p. Taken together, our findings revered that the feedback loop of lncRNA HCG11/miR-26b-5p/QKI-5 played a vital role in the physiological function of HUVECs, and this also provide a potential target for therapeutic strategies of As. © 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.