Abstract: Objective To observe the thyroid hormones in patients with type 2 diabetes. Methods One hundred and sixty-eight patients with type 2 diabetes were divided into four groups according to their glycosylated hemoglobin（GHbA1c） level（＜6.5%,6.5%-7.5%,7.6%-10.0%,＞10.0%）.The patients were further divided into no complication group,major vascular complication group,microvascular complication group,and major and microvascular complication group.Thyroid hormone levels were measured in all patients. Results The level of TT₃ and FT₃ was lower in patients with type 2 diabetes than in control group（P＜0.01）.The level of TT₃ and FT₃ was higher in 6.5%-7.5% and 7.6%-10.0% GHbA1c groups,and lower in ＞10.0% GHbA1c group than in GHbA1c＜6.5% group（P＜0.01）.The level of TT₃ and FT₃ was significantly lower in patients with complications than in those without complications. Conclusion The severer the type 2 diabetes is,the lower the thyroid hormone level is.