To date, the relationship between metabolic syndrome factors and the risk of glioma-related depression is still unclear, and no study investigates this relationship. Our aim was to investigate the relationship between metabolic syndrome factors and the risk of postoperative depression in high-grade patients. A total of 386 high-grade glioma patients participated in blood sample collection for metabolic syndrome factors analysis and the hospital anxiety and depression scale testing. The association between metabolic syndrome factors and the risk of postoperative depression was assessed using Cox regression proportional hazards models, and Student's t tests were used to evaluate the differences in demographic variables and clinical characteristics in subgroups. The incidence of postoperative depression in our 1.5-year follow-up was 30.5%. We found the risk of postoperative depression was elevated with increased blood glucose level [hazard ratios (HR) 2.277, 95% confidence interval (CI) 1.201-4.320, top vs. bottom quartile]. The hazard ratio was increased for z-scores of blood glucose (HR 1.672 per unit standard deviation, 95% CI 1.311-2.133] and of the combined metabolic syndrome score (HR 1.080, 95% CI 1.000-1.167). In addition, risk of postoperative depression risk was increased in high-grade glioma patients with high blood glucose levels (≥6.0 mmol/l) (HR 2.084, 95% CI 1.235-3.515). However, we did not find significant associations between postoperative depression and other metabolic syndrome factors, including body mass index, systolic blood pressure, diastolic blood pressure, cholesterol, and triglycerides. Depression is prevalent among patients with high-grade glioma after operation. Blood glucose level is positively associated with the risk of postoperative depression, and might be involved in the etiology of postoperative depression, and may predict its development in high-grade glioma patients.