〔Abstract〕 ObjectiveTo analyze the metabolic characteristics of tuberculous pleural effusion (TPE) and malignant pleural effusion (MPE) by non-targeted ultra–high performance liquid chromatography–mass spectrometry (UHPLC-MS), and to screen out potential metabolic markers for differential diagnosis between them. Methods Fifteen patients with pleural effusion in Hospital of Xinjiang Production and Construction Crops from October 2019 to August 2020 were collected, including TPE group (n = 8) and MPE group (n = 7). Non-targeted UHPLC-MS technique was used to analyze the metabonomics of two groups of pleural effusion samples in both positive and negative ion modes, and the receiver operating characteristic curve (ROC) analysis was carried out. Results TPE group compared with MPE group, 17 kinds of differential metabolites were screened, including 11 kinds of lipids and lipid-like molecules metabolites (64.7%), 2 kinds of organoheterocyclic compounds (11.7%), 1 kind of benzenoids, organic oxygen compounds, organic acids and derivatives and undefined substances (5.9% each). Among the 11 Lipids and lipid-like molecules differential metabolites, 5 were up-regulated in TPE group, in which linoleic acid methyl ester and teprenone were up-regulated by 62.25 and 19.35 times, and 6 were up-regulated in MPE group, with the highest up-regulation of 2.5 times. The area under curve (AUC) of 1–oleoyl–sn–glycero–3–phosphocholine, teprenone, linoleic acid methyl ester and 1–heptadecanoyl–sn–glycero–3– phosphocholine was more than 0.8. Conclusion 1–oleoyl–sn–glycero–3–phosphocholine, teprenone, linoleic acid methyl ester and 1–heptadecanoyl–sn–glycero–3–phosphocholine are up-regulated in TPE group, and preliminarily show good diagnostic effi cacyin TPE, suggesting that these metabolites are expected to be potential markers for differential diagnosis of TPE and MPE.