To explore the effects of Yiqi Huatan Xiaoying Formula combined with euthyrox on thyroid function in patients with hashimoto's thyroiditis(HT).Methods:A total of 69 cases of patients with HT in Tongling Hospital of Traditional Chinese Medicine from July，2017 to Dec.2019 were selected as the study objects and divided randomly into a control group(n=35)and an observation group(n=34).The control group were treated with euthyrox and selenious yeast tablets，and study group were treated with Yiqi Huatan Xiaoying Formula on the basis of control group.The 2 groups were treated for 12 weeks continuously.The clinical efficacy of 2 groups and the TCM syndrome score were compared，and the levels of thyroid hormones，autoantibodies were measured and compared.Results:The total effective rate of the treatment group was 85.29% after treatment，which was higher than 62.86% of control group(P<0.05); Compared with those before treatment，the TCM syndrome scores such as goiter，facial limb edema，mental fatigue，fear of cold and cold limb of 2 groups decreased evidently after treatment，and the observation group was lower than control group(P<0.01).Compared with those before treatment，the levels of TSH，TPOAb，TGAb in the 2 groups were significantly lower，and the observation group was lower than the control group(P<0.05 or P<0.01).The FT3、FT4 level of the 2 groups increased(P<0.01)，and the study group was higher than the control group(P<0.01).Conclusion:Yiqi Huatan Xiaoying combined with euthyrox in treating HT can reduce the levels of thyroid hormone，autoantibodies factors in patients，thereby improving patients 'thyroid function and promoting patients' clinical symptoms.