Background: Few studies in China have reported factors influencing suicide attempt in young first-episode drug free (FEDN) MDD patients. This study aimed to investigate the incidence and potential relevant factors of suicide attempt among young Chinese patients with FEDN MDD to prevent suicidal behavior in this population.Methods: We recruited 1076 FEDN MDD outpatients aged 18-45 years. Patients' mental states were measured by the Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), Positive and Negative Syndrome Scale (PANSS) positive subscale, and Clinical Global Impression Severity Scale (CGI-S). Fasting blood glucose, lipid levels, and thyroid function parameters were also measured.Results: The prevalence of suicide attempt for FEDN MDD patients was 18.31 %. Compared to patients without suicide attempt, patients with suicide attempt had an older age of onset, higher HAMA, HAMD, PANSS-positive subscale and CGI-S scores, higher blood pressure, fasting blood glucose, thyroid peroxidases antibody (A-TPO), anti-thyroglobulin (A-TG), thyroid stimulating hormone (TSH), low-density lipoprotein cholesterol (LDL-C), and total cholesterol (TC), but lower high-density lipoprotein cholesterol (HDL-C) (all p < 0.05). Logistic regression analysis showed that duration of illness, hypertension, PANSS-positive subscale, HAMA and CGI-S scores, and ATPO, LDL-C, TC, and HDL-C were associated with suicide attempt in patients with MDD. Limitations: The main limitations are cross-sectional design and inability to control selection bias.Conclusions: This study suggests that young patients with FEDN MDD have a high rate of suicide attempts. Several clinical and metabolic indicators related to lipids and thyroid function may be involved in suicide attempts in FEDN MDD patients.