Objective To explore the value of thyroid uptake rate of 131I and thyroid imaging with 99Tcm in diagnosis of subacute thyroiditis. Methods The examination results in 65 patients with subacute thyroiditis，65 patients with Graves' disease and 60 cases of normal control group were compared and analyzed. Results The thyroid uptake rate of 131I in patients with subacute thyroiditis was significantly lower than that of normal control, while the thyroid uptake rate of 131I in patients with Graves' disease was significantly higher than that of normal control. The radioactive distribution of thyroid images with 99Tcm were sparse or thyroids were not developing in patients with subacute thyroiditis, on the contrary, the radioactive distribution of thyroid images were progressively increased in patients with Graves' disease. Conclusion The thyroid uptake rate of 131I and the thyroid imaging with 99Tcm are very useful to improve accuracy of diagnosis in patients with subacute thyroiditis.