ObjectiveTo investigate the protective effect of Zuoguiwan against ⁶⁰Co-γ ray-induced premature aging of rats based on the phosphatidylinositol-3-kinases/protein kinase B/mammalian target of rapamycin （PI3K/Akt/mTOR） signaling pathway. MethodSixty sexually mature female SD rats were irradiated with ⁶⁰Co-γ rays （6.0 Gy， LD₄₀） for 24 h at one time. Then they were randomized into model group， Bujiale group （0.18 g·kg^-1·d^-1）， Bujiale （0.09 g·kg^-1·d^-1） + high-dose Zuoguiwan group （23.625 g·kg^-1·d^-1）， high-dose Zuoguiwan group （23.625 g·kg^-1·d^-1）， medium-dose Zuoguiwan group （9.45 g·kg^-1·d^-1）， and low-dose Zuoguiwan group （4.725 g·kg^-1·d^-1）. The administration （once a day） lasted 21 days. Serum indexes ［follicle-stimulating hormone （FSH）， luteinizing hormone （LH）， and estradiol （E₂）］ of rats were detected by enzyme-linked immunosorbent assay （ELISA）， and morphological changes of ovarian tissues were observed based on hematoxylin and eosin （HE） staining. The apoptosis rate of granulosa cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） and the protein expression of phosphorylated （p）-PI3K， p-Akt， p-mTOR， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax） in ovarian tissues by Western blot. ResultCompared with normal group， model group demonstrated increase in serum FSH （P<0.01）， decrease in E₂ （P<0.05）， and reduction of follicles and luteum in early ovary （P<0.01）. Moreover， the elevation of apoptosis rate of granulosa cells （P<0.01）， down-regulation of p-PI3K， p-Akt， p-mTOR， and Bcl-2 in ovarian tissue， and increase in expression of Bax were also observed in the model group as compared with the normal group （P<0.01）. In comparison with the model group， the administration groups showed rise of the number of early ovarian follicles， decrease in the apoptosis rate of granulosa cells， increase in the expression of p-PI3K， p-Akt， p-mTOR， and Bcl-2， and down-regulation of Bax， particularly the Bujiale + high-dose Zuoguiwan group（P<0.05，P<0.01）. ConclusionZuoguiwan protects radiation-damaged ovary by activating the expression of PI3K/Akt/mTOR protein in ovarian tissue， increasing Bcl-2， and inhibiting the expression of Bax.