Objective To explore the clinical effect of 131 I treatment in patients with graves of hyperthyroidism with ATD drug reaction. Methods 95 patients with graves of hyperthyroidism had more than one time to ATD drug reaction were involved in this study. The serum levels of TT3, TT4, FT3, FT4, TSH, TGAB, TMAB and TRAB in patients before 131 I therapy were detected. The mass of thyroid in patients were estimated by CT imaging, and the iodine uptake rate of thyroid in patients was determined. The patients were taken one does of 131I and followed for one year. Results Among 95 patients, 75 cases were complete remission which including 13 cases of thyroid function decrease and 14 cases were partial remission. The total effective rate was 93.68%. The thyroid mass in these complete and partial response cases were decreased from 42.6 ± 15.4 g before the treatment to 29.8 ±8.5 g (P < 0.01). Conclusion CT imaging has great application value to estimate the thyroid weight. 131 I therapy for patients with graves of hyperthyroidism with ATD drug reaction is very safe, simple and effective treatment of choice.