Objective:To study the effect of total flavonoids of Rhizoma Drynariae on learning and memory impairment mice induced by sodium nitrite. Methods:75 mice were divided into blank group, model group, Kangnaoshuai capsule group, Rhizoma Drynariae total flavonoids group and Rhizoma Drynariae total flavonoids+inhibitor group according to the random number table method, with 15 mice in each group. The Kangnaoshui Capsule group was administered with Kangnaoshui Capsule 585 mg/kg, the Rhizoma Drynariae total flavonoids group was administered with the Rhizoma Drynariae total flavonoids 97.5 mg/kg, the Rhizoma Drynariae total flavonoids group and the inhibitor group were administered with the Rhizoma Drynariae total flavonoids by intragastric administration 97.5 mg/kg, and intraperitoneal injection of 0.072 mg/kg ICI182780 for 21 days, once a day. The model was established on the 22nd day. Except for the blank group, the other mice were injected with sodium nitrite intraperitoneally to replicate the mice model with impaired learning and memory capability. The learning and memory capabilit of mice were detected with water maze method, and the estrogen receptor in hippocampus was detected by immunohistochemistry β (estrogen receptor β, ERβ). The expression of ERβ in hippocampus and the expression of phosphorylated P38 (P-P38) and the protein contents of B-cell lymphoma-2 (Bcl-2), Bcl-2 associated death promoter (Bad) and Caspase-3 in the apoptotic system was detected by Western blot. The kit was used to detect MDA,SOD and NO protein content in hippocampus. Results:The latency of Rhizoma Drynariae total flavonoids group was significantly shorter than the model group, the number of crossing platform and the residence time in the target quadrant were significantly increased ( P<0.01); The expression of ERβ Protein in mice hippocampus (0.371 ± 0.010 vs. 0.124 ± 0.009), Bcl-2 protein (1.146 ± 0.028 vs. 0.726 ± 0.016) and the contents of SOD [(153.657 ± 6.385) U/mg vs. (67.719±5.845) U/mg] increased significantly ( P<0.01); The expression of P-P38/P38 protein (0.412 ± 0.043 vs.0.806 ± 0.069), Bad protein (0.421 ± 0.010 vs.0.633 ± 0.010), Caspase-3 protein (0.923 ± 0.042 vs.1.437 ± 0.033), and the content of MDA [(8.669 ± 0.662) nmol/mg vs. (11.772 ± 1.054) nmol/mg] and NO [(4.259 ± 0.225) nmol/mg vs. (10.805 ± 0.415) nmol/mg] decreased significantly ( P<0.01). In addition, ER blocker can antagonize the above recovery and improvement effects of Rhizoma Drynariae total flavonoids group. Conclusion:Rhizoma Drynariae total flavonoids can regulate memory impairment, inhibit neuronal apoptosis and reduce oxidative stress in sodium nitrite model mice through ER-P38/MAPK signal pathway.