〔Abstract〕 Objective To investigate the effect of inhibiting proprotein convertase subtilisin/kexin type 9(PCSK9) on the calcification of human aortic endothelial cells(HAEC) induced by dexamethasone combined with L-ascorbic acid and β-glycerophosphate. Methods Different concentrations(0, 10, 30, 50 mmol/L) β glycerophosphate + 50 μg/ml L-ascorbic acid + 100 nmol/L dexamethasone were used to stimulate HAEC, and the optimal concentration was selected to induce cellular calcification. The mRNA and protein expression of PCSK9 in HAEC was verified. Small interfering RNA(siRNA) was used to knock down the expression of PCSK9 in HAEC, and cell calcification was induced by the same conditions, and the expression changes of PCSK9 and major calcification indexes in HAEC were detected after PCSK9 knockdown. Alizarin red S staining was used to observe the calcification deposition in the cells. Results (1) When the β glycerophosphate concentration was 30 mmol/L, the mRNA and protein expression levels of the main calcification indicators bone morphogenetic protein(BMP)2, BMP4 and Runt-related transcription factor 2(RUNX2) in HAEC reached the peak, and the effect of inducing calcification was the best;(2) The mRNA and protein expression levels of PCSK9 significantly increased after HAEC calcification was induced;(3) Knockdown of PCSK9 expression in cells could significantly inhibit HAEC calcification inducedin vitro, the expression of calcification-related genes and proteins significantly reduced, and the intracellular calcium salt deposition significantly reduced. Conclusion The expression of PCSK9 is related to the calcification level of HAEC. Knockdown of PCSK9 can inhibit the calcification of HAEC induced by dexamethasone combined with ascorbic acid and β-glycerophosphate.