Objective: To explore the effect of miR-199a on the viability and apoptosis of rat cerebral cortical neurons cells induced by hypoxia/reoxygenation. Methods: Rat cerebral cortical neurons cells were cultured in vitro and treated with hypoxia/reoxygenation to establish the cell injury model and recorded as Model group, and normal cultured cells were used as control (Con) group. Empty vector and miR-199a mimic were respectively transfected into rat cerebral cortical neurons cells, and then hypoxia/reoxygenation cell injury models were established, which were recorded as Model + NC group or Model + miR-199a mimic group, respectively. After miR-199a mimic was transfected into rat cerebral cortical neurons cells, PI3K-AKT signaling pathway inhibitor LY294002 was added for treatment, and then hypoxia/reoxygenation cell injury model was established and recorded as Model + miR-199a mimic + LY294002 group. Then, the expression of miR-199a was detected by RT-PCR, the cell cycle and apoptosis rate were detected by flow cytometry, the cell viability was detected by MTT, and the expression of Cleaved-caspase3, pro-caspase3, p-PI3K and p-AKT proteins were detected by Western blot. Results: Compared with Con group, the expression level of miR-199a, cell viability, S-phase cell proportion and the expression levels of pro-caspase3, p-PI3K and p-AKT protein in Model group were significantly lower, while the cell proportion of G₀–G₁ phase, the apoptosis rate and the expression level of cleaved-caspase3 protein were significantly higher in Model group (P<0.05). Compared with the Model + NC group, the cell viability, the proportion of S-phase cells and the expression levels of pro-caspase3, p-PI3K and p-AKT protein in the Model + miR-199a mimic group were significantly increased, while the proportion of G₀–G₁ phase cells, the rate of apoptosis and the expression level of cleaved-caspase3 protein were significantly decreased (P<0.05). Compared with the Model + miR-199a mimic group, the cell viability, the proportion of S-phase cells and the expression level of pro-caspase3 protein in the Model + miR-199a mimic + LY294002 group were significantly decreased, and the proportion of G₀–G₁ phase cells, the apoptosis rate and the expression level of cleaved-caspase3 protein were significantly increased (P<0.05). Conclusion: The overexpression of miR-199a could improve the viability of rat cerebral cortical neurons cells induced by hypoxia/reoxygenation and inhibit cell apoptosis, thereby reducing cell damage. The above biological effects may be achieved by activating PI3K-Akt signaling pathway.