ObjectiveTo investigate the correlation between serum levels ofthyroglobulin antibody (TGAb),thyroid peroxidase antibody (TPOAb) and hypothyroidism incidence in Graves disease after 131Ⅰ therapy.MethodsThree hundred and twenty-five patients with Graves disease whose TGAb and TPOAb were negative before treatment were selected.Serum levels of FT3,FT4,TSH,TGAb and TPOAb were measured at the 3rd,6th,12th and 18th month after treatment respectively.All cases were divided into positive group and negative group according to the serum levels of TGAb and TPOAb at the 18th month after 131Ⅰ treatment.The hypothyroidism incidences of two groups were compared.ResultsThere were 271 cases in negative group and 54 cases in positive group.The hypothyroidism incidence was 7.4％(24/325),and the incidence of negative group was 3.0％ (8/271),while the incidence of positive group was 29.6％ (16/54).There was significant difference between two groups(P ＜ 0.05).ConclusionsHypothyroidism incidence of Graves disease after 131Ⅰ therapy has obvious correlation with the serum levels of TGAb and TPOAb.Dynamic observation of the serum levels of TGAb and TPOAb in Graves disease after 131Ⅰ therapy has important significance for clinical guiding and prognosis judgement.