Abstract： Objective To study the protective effects of quercetin on primary cultured rat astrocytes against oxidative stress. Methods Oxidative stress in primary cultured astrocytes was induced by exposure to 2 mmol/L H2O2 for 6 h, and the protective effect of quercetin pretreatment at different concentrations (0, 50, 100, and 200 μmol/L) administered 24 h before H2O2exposure was assessed with lactic dehydrogenase (LDH) release assay and live-dead staining. Results Treatment with 2 mmol/L H2O2 caused obvious injuries to the astrocytes, resulting in significantly increased LDH release rate in comparison with that of the normal control cells [(90.27±2.68)% vs (3.89±+1.89)%, P<0.05] and significantly lowered cell survival rate [(59.73%±9.92)% vs (99.25±0.08)%, P<0.05]. Pretreatment with quercetin decreased the LDH release rate and increased the survival rate of the astrocytes exposed to H2O2; at the concentration of 50, 100, and 200 μmol/L, quercetin significantly decreased the LDH release rate of the exposed cells to (48.19±13.98)%, (27.81±9.33)% and (18.13±8.28)% (P<0.05), and increased the cell survival rate to (86.80±3.62)%, (88.32±5.77)% and (91.18±3.03)%, respectively (P<0.05). Conclusion Quereetin may produce protective effects on the primary cultured astrocytes against oxidative stress.