Objective:To investigate the serum metabolites and their metabolic characteristics of patients with optic neuritis.Methods:Case-control study. From January 2021 to January 2022, 9 serum specimens of diagnosed patients with optic neuritis were collected in Department of Neurology from Beijing Tongren Hospital and 9 healthy subjects as the control. Among them, there were 5 females and 4 males in the optic neuritis group, aged (35.8±12.9) years; there were 5 females and 4 males in the healthy control group, aged (32.6±8.6) years. Liquid chromatography-mass spectrometry was used to detect metabolites in serum of healthy control and patients with optic neuritis. The principal component analysis (PCA) and orthogonal partial least-squares discriminination analysis (OPLS-DA) were used to analyze the differential metabolites . The variable importance projection value of OPLS-DA model and the P value of t-test was applied to find the different metabolites. Results:Thirty-seven metabolites were finally identified from serum samples. Four metabolites with variable important in projection (VIP) values larger than 1 and P values less than 0.05 were teased out, three metabolites, LysoPC (P-16∶0), LysoPC (16∶0), LysoPC (P-18∶0) belonge to phospholipid and one metabolite was L-Threonine, they were all down-regulated. The area under curve were 0.951, 0.889, 0.963 and 0.944, respectively. Conclusion:Based on metabonomic analysis, some metabolites in serum have changed, which can provide basis for biomarkers screening of optic neuritis.