Abstract: Objective To investigate the changes of thyroid autoantibody and serum selenium levels in patients with type 2 diabetes and influencing factors. Methods Fifty patients with diabetes (30 patients with type 2 diabetes and 20 patients with type 1 diabetes) were selected as case group, and 50 healthy persons were selected as control group. Chemiluminescence assay was conducted to detect antithyroid peroxidase antibody (TPOAb) and anti-thyroglobulin antibody (TGAb) for 2 groups. Meanwhile, competitive enzyme-linked immunosorbent assay was conducted to detect thyroid stimulating hormone receptor antibody (TRAb) levels. The serum selenium levels of both case group and control group were determined with atomic fluorescence spectrometry. The differences between 2 groups and the relationships between the serum selenium levrel and thyroid autoantibody levels were observed. Results The serum levels of TPOAb, TRAb, TGAb in diabetes group were significantly higher than those in control group (t = 3.246, 4.017, 3.267, P0.05), whereas the serum selenium level in diabetes group was significantly lower than that in control group (t = -6.794, P0.05) . In addition, the TGAb and serum selenium levels in the patients with type 2 diabetes were significantly higher than those in patients with type 1 diabetes(t = 2.143, 3.012, P0.05). Analysis showed that there was a negative correlation between the serum selenium levels and TRAb level (r = -0.767, P0.05). Conclusion There are changes in thyroid autoantibody and serum selenium levels in patients with diabetes. There is a negative correlation between serum selenium level and TRAb level in patients with type 2 diabetes.