To investigate the effects and related mechanism of acanthopanax senticosus injection (ASI) on ovarian function in rats with polycystic ovary syndrome (PCOS). The PCOS rat model was prepared by continuously gavage of letrozole (1 mg/kg) for 21 days, and the normal group, model group, ASI group, activator group and inhibitor group, with 8 rats in each group. After 4 weeks of treatment, the body mass was weighted, the level of fasting blood glucose and fasting insulin in serum were measured, and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. The level of anti-mullerian hormone (AMH), testosterone (T), estradiol (E₂), luteinizing hormone (LH) and follicle stimulating hormone (FSH) in serum were measured by ELISA, and the LH/FSH was calculated. The ovarian index was calculated. The pathological changes and cell apoptosis ovarian tissue was examined by hematoxylin-eosin (HE) staining or TdT mediated dUDP nick end labeling (TUNEL) staining. The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), catalase (CAT) in ovarian tissues were detected by spectrophotometer staining. The mRNA expression of Nrf2, HO-1 were detected by RT-qPCR; the protein expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), B-lymphomatoma-2 (Bcl-2), Bcl-2 related X protein (Bax), Caspase-3 (Cas-3), Cleaved Caspase-3 (C-Cas-3) were detected by Western blot. The results showed that: compared with the model group, the body mass, HOMA-IR and the level of fasting blood glucose, fasting insulin, AMH, T, LH and LH/FSH decreased for the rats in the ASI group and activator group, and the level of E₂, FSH increased. The pathological changes of ovarian tissue were improved, the ovarian index, cystic follicle number and apoptosis index of ovarian cell were decreased, and the corpus luteum number was increased. The content of MDA in ovarian tissue was decreased, the activity of SOD and CAT were increased. The mRNA expression level of Nrf2, HO-1 and the protein expression level of Nrf2, HO-1, Bcl-2 increased, the protein expression level of Bax, C-Cas-3 and the C-Cas-3/Cas-3 decreased. All of the differences were statistically significant (P<0.05). Compared with the ASI group, the activator group showed significantly enhanced effects on various detection indicators in PCOS rats, while the inhibitor group showed significantly weakened effects on various detection indicators, the differences were statistically significant (P<0.05). Studies have showed that ASI may improve ovarian function in PCOS rats by upregulating the Nrf2/HO-1 pathway, which providing a new approach for PCOS treatment.