To explore the changes of autophagy and injury in different time periods after PC12 cell were induced by oxygen-glucose deprivation/reoxygenation (OGD/R), and the intervention effects of Astragaloside IV.Methods:Firstly, the changes of autophagy at different time periods and the relationship with cell damage after PC12 cell oxygen-glucose deprivation/reoxygenation (OGD/R) was probed to determine the point that autophagy contributed to cell injury, then the the injury model of PC12 OGD/R was established to investigate the effect of Astragaloside IV against autophagy injury.Results:After reoxygenation for 6～36 h, cell survival rate decreased, the leakage rate of LDH increased. Pretreated with 3-mA, cell survival rate decreased significantly, LDH leakage rate increased remarkably after reoxygenation for 6～12 h, while being opposite after reoxygenation 24～36 h. Confocal microscopy and western-blot showed that the autophagosome was formed after reoxygenation for 6 h and LC3-Ⅱ, LC3-Ⅱ/LC3-Ⅰwas increased, getting to the maximum at 24 h after reoxygenation. The expression of p62 protein decreased gradually along with time. Astragaloside IV could remarkably inhibit cell autophagy followed by PC12 cell OGD/R 24 h and presented dose dependence.Conclusion:Autophagy may reduce the damage of nerve cells at 6～12 h after reoxygenation, however, excessive autophagy aggravates the damage after reoxygenation for 24～36 h; Astragaloside IV exerts the protective effect from the injured cells through inhibiting the cell damage induced by excessive autophagy.