〔Abstract〕 Objective To investigate the correlation between thyroid stimulating hormone(TSH) level and metabolic syndrome(MS) in subclinical hypothyroidism(SCH) in a district in Hefei City. Methods Using the method of cluster sampling survey, according to the inclusion and exclusion criteria, 2 628 permanent residents aged over 18 years(living time≥5 years) in a district of Hefei City were enrolled. Based on the the thyroid function, subjects were divided into SCH group and normal thyroid function group(control group); According to MS diagnostic criteria, they were divided into MS group and non-MS group; According to the trisection of TSH level, SCH group was divided into three subgroups: low TSH level, medium TSH level and high TSH level. The differences of clinical parameters between different groups were compared. Logistic regression analysis was used to investigate the risk of MS in different TSH levels of SCH patients and the independent influencing factors of MS. Receiver operating curve(ROC) was used to explore TSH as a potential biomarker for the diagnosis of MS in SCH patients. Results The detection rate of SCH was 19.29%(507/2 628) and that of MS was 29.45%(774/2 628). Compared with the control group, the detection rate of MS in SCH group was significantly higher(34.91% vs 27.99%,P=0.002); In SCH group, the detection rate of MS increased gradually with the increase of TSH level(trend χ2= 13.717,P=0.001). Compared with the control group, the risk of MS in SCH patients with high TSH level increased by 1.722 times(OR= 1.722, 95%CI1.702～2.885,P=0.009). Multiple logistic regression analysis found that TSH was an independent risk factor for MS(OR=1.850, 95%CI1.625～2.002). ROC analysis showed that the area under the curve(AUC) of TSH was 0.811(95%CI0.696～0.904), the optimal cutoff point of TSH was 8.76 mIU/L, and the sensitivity and specificity were 87.5% and 73.9% respectively. Conclusion The prevalence of MS in SCH patients increased gradually with the increase of TSH level in Hefei City. TSH is an independent risk factor for MS, and can be used as a diagnostic marker for MS in SCH patients.