Background: Glucose metabolism is related to depression, but the relationship between blood glucose and suicide attempts in patients with major depressive disorder (MDD) remains unclear. This large-scale sample explores the relationship between suicide attempts and fasting blood glucose, in addition to sex differences in first-episode and drug naive (FEDN) MDD patients. Methods: 1718 FEDN MDD patients diagnosed for the first time were recruited, and their demographic data, clinical data, and blood glucose indicators were collected. 17-item Hamilton Depression Rating Scale (HAMD), 14-item Hamilton Anxiety Rating Scale (HAMA), and positive subscale of the Positive and Negative Syndrome Scale (PANSS) were used to assess their depression, anxiety and psychotic symptoms, respectively. Results: The depression, anxiety, psychotic symptoms and blood sugar levels of the suicide attempt group were higher than those of the non-suicide attempt group. Correlation analysis showed that blood glucose was significantly associated with suicide attempts in male and female patients. While binary logistic regression showed that blood glucose levels were significantly associated with suicide attempts in male patients, it showed that suicide attempts were not significantly associated with blood glucose levels in female patients. Limitations: The main limitations are cross-sectional design and inability to control selection bias. Conclusions: In male MDD patients, fasting blood glucose level is a potential biomarker of suicide attempt, which deserves attention to avoid suicide risk. However, in female patients, fasting blood glucose has no significant correlation to suicide attempts.