Objective To investigate the relationship between subclinical hypothyroidism (SCH) and diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM). Methods A total of 792 patients of T2DM were enrolled in the study. There were 448 males and 344 females, with an average age of (54.13±13.06) years. The average duration of diabetes was (8.03±6.70) years. The patients were grouped according to the degree of DR and thyroid function. Among them, 483 patients (61.0%) were no DR, 240 patients (30.3%) were mild DR, 69 patients (8.7%) were severe DR. 725 patients (91.5%) were normal thyroid function, 67 patients (8.5%) were SCH. The prevalence of SCH among no DR group, mild DR group and severe DR group was compared. And the prevalence of DR between normal thyroid function group and SCH group was compared. Logistic regression analysis was used to estimate the association between SCH and DR. Results No significant differences among the three groups (no DR group, mild DR group, severe DR group) were found in the prevalence of SCH (χ2=1.823,P=0.402). There were no significant differences in the incidences of DR between normal thyroid function group and SCH group (χ2=1.618,P=0.239). Logistic regression analysis demonstrated that SCH was not significant associated with DR [mild DR: odds ratio (OR)=1.361, 95% confidence interval (CI)=0.773−2.399,P=0.286; severe DR:OR=1.326, 95%CI=0.520−3.384,P=0.555; DR:OR=1.353, 95%CI=0.798−2.294,P=0.261). Conclusion SCH is not significant associated with DR in patients with T2DM.