Objective To investigate the clinical significance of differential metabolites of three unsaturated fatty acids in ascites of ovarian cancer. Methods According to no chemotherapy and chemotherapy, chemosensitivity and chemotherapy resistance,37 cases of ovarian cancer ascites (including supernatant and precipitated cells) and 22 cases of ovarian cancer tissue samples were selected and divided into two groups for ultra-high performance liquid chromatography tandem time-of-flight mass spectrometry UHPLC-Q-TOF / MS analysis, combined with human metabolome database and multivariate statistical analysis, 46 differential metabolites were detected in each of the two groups. From the point of view of fatty acid metabolism, three differential metabolites involved in biosynthesis of unsaturated fatty acids (UFA) were screened.They are adrenic acid ,arachidic acid and dihomo-γ-linolenic acid(DGLA).Results The changes of metabolic peak intensity and the correlation between the coding genes of upstream and downstream related enzymes in the database [acyl-CoA thioesterase (ACOT code), desaturase (FADS code), etc.] showed that the changes of their metabolic levels were positively correlated with the expression levels of serum CA125 and other markers in patients. Conclusion Changes in the metabolic levels of arachidic acid,adrenic acid and DGLA in ascites of ovarian cancer may affect the prognosis of ovarian cancer to a certain extent.