OBJECTIVE To investigate the mechanisms of paeoniflorin （PF） in anti-hyperprolactinemia （HPRL）. METHODS Twenty-four female SD rats were divided into blank control group （intragastric administration of 5% gum arabic solution）， olanzapine group （model group， intragastric administration of 5 mg/kg olanzapine suspension）， and PF group （intragastric administration of 5 mg/kg olanzapine suspension， followed by gavaging with 50 mg/kg PF solution 2 hours later） with 8 rats in each group. Once a day， continuously model/administer until the plasma prolactin （PRL） levels in the olanzapine group were twice as high as those in the blank control group. PRL levels were measured. The changes in gut microbiota of rats were analyzed， including assessments of α-diversity （Simpson， Chao1， and Shannon indexes）， β-diversity， species composition analysis （at the phylum and genus levels）， and microbiome LEfSe analysis. Fecal untargeted metabolomics technology was employed to analyze the effects of PF on the fecal metabolomics of rats， including multivariate statistical analysis， screening of differential metabolites， and pathway enrichment analysis. Spearman correlation analysis was performed to examine the correlations between differential microbiota and differential fecal metabolites. RESULTS PF significantly reduced serum PRL levels of rats in olanzapine group （P＜0.05）. 16S rRNA sequencing revealed that PF improved the α-diversity and β-diversity of gut microbiota in HPRL rats （P＜0.05）， restoring them to levels similar to the blank control group. At the phylum level， PF significantly reduced the relative abundance of Firmicutes and Desulfobacterota， while increasing the relative abundance of Verrucomicrobiota in HPRL rats （all P＜0.05）. At the genus level， PF reversed the relative abundance of Desulfovibrio，Allobaculum， and Prevotellaceae_NK3B31_group， etc （all P＜0.05）. The results of LEfSe analysis revealed that PF significantly enriched microbial taxa such as Actinobacteriota，Staphylococcales， Corynebacteriales， etc （all P＜0.05）. Metabolomics analysis identified 51 differential metabolites， with key metabolic pathways enriched in steroid hormone biosynthesis， prostate cancer， ovarian steroidogenesis， etc. Correlation analysis showed that the relative abundance of gut microbiota such as Desulfovibrio and Aerococcus was significantly correlated with the levels of steroid hormone metabolites such as tetrahydrocortisol and adrenosterone （P＜0.05）. CONCLUSIONS PF alleviates PRL by modulating gut microbiota structure in HPRL rats （including significantly reducing the relative abundance of Desulfovibrio， Allobaculum and Aerococcus， as well as significantly increasing the relative abundance of Ruminococcaceae_UBA1819 and Muribaculum）， and regulating steroid hormone pathways， then exerting its anti-HPRL effect.