Abstract： Objective： To observe the clinical effect of the therapy of Qinggan Sanjie Xiaoying Prescription combined with Levothyroxine Sodium on Hashimoto thyroiditis and its influence on immune function and oxidative stress. Methods：A total of 63 patients with Hashimoto thyroiditis were divided into the control group (31 cases) and the observation group (32 cases) by random number table method. The control group was treated with Levothyroxine Sodium，and the observation group was additionally treated with Qinggan Sanjie Xiaoying Prescription combined with Levothyroxine Sodium. Both groups were treated continuously for 12 weeks. Before and after treatment， traditional Chinese medicine (TCM) syndrome scores， thyroid autoantibody， thyroid function， immune function and oxidative stress levels were compared between the two groups. Results：The total effective rate was 93.75% in the observation group， higher than that of 67.74% in the control group (P＜0.05). After treatment， the TCM syndrome scores， thyroid peroxidase antibody (TPOAb)， thyroglobulin antibody (TGAb)， thyroid stimulating hormone (TSH)， CD8+ and malondialdehyde levels in the two groups were all decreased when compared with those before treatment (P＜0.05)； the activity levels of free triiodothyronine (FT3)， serum free thyroxine (FT4)，CD3+， CD4+，superoxide dismutase and glutathione peroxidase were increased when compared with those before treatment (P＜0.05). After treatment，the TCM syndrome scores，thyroid autoantibody，TSH，CD8+ and malondialdehyde levels in the observation group were lower than those in the control group (P＜0.05)，and the activity levels of FT3， FT4， CD3+ ， CD4+ ， superoxide dismutase and glutathione peroxidase in the observation group were higher than those in the control group (P＜0.05). Conclusion： The therapy of Qinggan Sanjie Xiaoying Prescription combined with Levothyroxine Sodium for Hashimoto thyroiditis can improve the thyroid function，reduce the oxidative stress reaction，enhance the immune function，and has a significant clinical effect.