Abstract: Objective To explore the diagnostic value of serum thyroglobulin antibody (TGAb),thyroid microsomal antibody (TMAb)and thyroid peroxidase antibody (TPOAb)in au-toimmune thyroid disease (AITD).Methods 100 patients with thyroid dysfunction were divided into hyperthyroidism group and hypothyroidism group according to the levels of serum triiodothy-ronine (T3),thyroxine (T4)and thyroid stimulating hormone (TSH),50 cases in each group.An-other 50 patients with normal thyroid function were collected and designed as control group.5 mL venous blood was collected,and the serum was separated.The levels of TGAb,TMAb,TPOAb, T3,T4 and TSH were detected by radioimmunoassay in each group,positive rates of TGAb,TMAb and TPOAb were observed,and the serum levels of positive TGAb,TMAb and TPOAb were com-pared among all the groups.Results The positive rate of serum TPOAb was significantly higher than those of TGAb and TMAb in hyperthyroidism group and hypothyroidism group.The positive rates of serum TGAb,TMAb and TPOAb in hyperthyroidism and hypothyroidism groups were sig-nificantly higher than the control group,and those in hypothyroidism group were higher than hy-perthyroidism group.The levels of serum TGAb,TMAb and TPOAb in hyperthyroidism group and hypothyroidism group were significantly higher than the control group,and those in hypothyroidism group were obviously higher than hyperthyroidism group.Conclusion TPOAb shows an important significance in diagnosing AITD,which provides an important evidence for AITD diagnosis, treatment and prognosis.