Endothelial barrier dysfunction is a critical pathophysiological process of pulmonary ischemia/reperfusion (I/R) injury in patients scheduled for cardiopulmonary bypass. Impaired actin cytoskeleton dynamics and cell-cell junctions are the main causes of endothelial dysfunction. Statins have protective effects on I/R-induced lung injury; however, the mechanism is unclear. We explored the therapeutic potential of simvastatin (SV) in endothelial cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R). SV pretreatment promoted the barrier function of human pulmonary microvascular endothelial cells (HPMECs) subjected to OGD/R. LY294002 was used to evaluate the role of the PI3K/Akt pathway in regulating the barrier function of HPMECs subjected to OGD/R. LY294002 suppressed the barrier function of HPMECs. SV restored the endothelial barrier function by rescuing endothelial cell migration and permeability, which are involved in the regulation of cytoskeleton dynamics and intercellular junction expression via the PI3K/Akt signaling pathway.