To explore the mechanism of Baijin capsule in the treatment of depression based on metabolomics.Methods:SD rats modeled by Chronic Unpredictable Mild Stress were made as experimental objects.The effect of modeling and antidepressant efficacy of Baijin capsule was appraised before the study of brain metabolomics with the results of determination including the body weight,sucrose consumption and open field trial.Additionally,the study attempted to find out the biological information related to depression in samples of brain tissue based on brain metabolomics research.Pharmacokinetics research was obtained by the combined result of LC-MS/MS and analytical software SPSS/SIMACA-P and retrieval of database (MASSBANK,METLIN,HMDB and KEGG) and literature analysis.Results:One thousand one hundred and ninty four compounds were determined by Metabolomics.The results of PCA and OPLS- DA indicated that the score matrix in normal group,CUMS group and drug group were distributed in three different areas which meant that there was a difference between groups.Four main indicators of compound taurine,threonic acid，N-acetylaspartate and inosine were identified by integrating load matrix,library search and literature analysis.Conclusion:Baijin capsule is able to regulate the brain as an antidepressant by adjusting the levels of amino acids,effecting on central nervous system of neurotransmitter and energy metabolism.