Abstract: To explore the mechanism of Lvjiaobuxue Granule (LBG) in improving postpartum Qi and blood deficiency in rats through milk metabolomics combined with biological target network analysis, the model of postpartum Qi and blood deficiency in rats was established by "orbital bloodletting combined with exhaustive swimming under negative gravity". The behavioral indexes, blood routine parameters, immune organ index and changes of immunoglobulin G (IgG) in milk of rats were detected to evaluate the improvement effect of LBG on postpartum Qi and blood deficiency in rats. LC-MS milk metabolomics was applied to find the differential metabolites in the milk of rats with postpartum Qi and blood deficiency model regulated by LBG. Combined with biological target network analysis, the material basis of the efficacy, action targets and signaling pathways of LBG in improving postpartum Qi and blood deficiency were predicted, and molecular docking was used for verification. The animal experiments in this study were conducted in compliance with the regulations of the Scientific Research Ethics Committee of Shanxi University and approved by the Animal Experimentation Ethics Review (approval No.: SXULL2023022). LBG significantly improved the abnormal behavior, decreased blood routine parameters, immune organ damage and decreased IgG in milk of rats with postpartum Qi and blood deficiency model (P < 0.05, P < 0.01). Twenty endogenous metabolites were found to be differential in milk, serving as potential biomarkers for LBG to improve postpartum Qi and blood deficiency in rats, and these metabolites mainly included amino acids, fatty acids and nucleotides, etc. Biological target network analysis showed that its potential mechanism might be related to the signaling pathway of steroid hormone biosynthesis. The key components in LBG, luteolin, caffeic acid and ferulic acid, might respectively regulate the core targets of CYP19A1, CYP1A1, CYP1A2 and CYP3A4, affect the changes of linoleic acid endogenous metabolites in milk, and regulate the biosynthesis of steroid hormones to play its role in improving postpartum Qi and blood deficiency. In addition, the results of molecular docking showed that the three key components in LBG had significant binding effects with their core targets. LBG may affect the linoleic acid level in milk by regulating CYP19A1, CYP1A1, CYP1A2 and CYP3A4 with luteolin, ferulic acid and caffeic acid respectively, and then regulate the signaling pathway of steroid hormone biosynthesis to improve postpartum Qi and blood deficiency in rats.