Abstract: Objective To explore the effect of the concentration of serum thyrotropin receptor antibody (TRAb) before the first 131I therapy on the treatment efficacy in patients with newly diagnosed with Graves disease. Methods 477 newly diagnosed Graves’ disease (GD) patients were collected from Jan to May 2013 in our clinic. The serum thyroid function indexes, serum thyroid peroxidase antibody (TPOAb), thyroglobin antibody (TGAb), TRAb and peak of 131I uptake rate within 24 hour were tested. The volume of thyroid was measured by SPECT and the patients were all treated with 131I. Results One year of follow-up after 131I therapy in all 477 patients, 249 cases of thyroid function were in euthyroid (52.2%), 142 cases in unhealed (29.8%), 86 cases composed hypothyroidism (18%). The logistic regression analysis showed that thyroid volume and TRAb concentration effected the treatment efficacy and prognosis (OR = 0.876 and 0.892). The ROC curve analysis showed that when the value of newly diagnosed GD patients TRAb was more than 21.74 IU/L, the possibility of unhealed outcome of first 131I therapy was increased; when the value of TRAb was less than 9.47IU/L, it would be more likely to be hypothyroidism. Conclusion The concentration of TRAb and thyroid volume could affect prognosis of GD patients after 131I therapy.