Existing research suggests the involvement of a brain-liver-communication-related mechanism in the occurrence of depression. In this study, we selected Chaihu-Shugan-San (CSS), a traditional Chinese herbal medicine that can simultaneously affect liver and depression, as a probe to investigate the involvement of the brain-liver-communication-related mechanism in perimenopausal depression. A total of 50 experimental perimenopausal depression rat models were established by ovariectomy surgery (PMS) followed by chronic unpredictable mild stress (CUMS) processes. Animals underwent CSS treatment or treatments with CSS + Ly294002, an inhibitor of the PI3K/Akt signalling pathway. We observed the behavioural performances of depression and anxiety, serum concentrations of biochemical indices, serum estrogen two levels, hippocampal 5-HT and NE levels and the morphological changes in liver tissues. The protein and mRNA expressions of PI3K and Akt were also evaluated. CSS treatment significantly ameliorated the behavioural performance, partial biochemical indices and the morphological changes in the liver tissues of PMS + CUMS rats. Ly294002 partially inhibited the CSS effects. The expressions of PI3K and Akt were significantly downregulated by PMS + CUMS processes but upregulated by CSS treatment, which could be significantly suppressed by Ly294002. A brain-liver-communication-related mechanism may be involved in perimenopausal depression, where the PI3K/Akt signalling pathway plays a vital role.