Abstract：Objective：To observe the clinical effect of Yiqi Yangyin Decoction for patients after surgery for thyroid cancer and its effect on thyroid function and traditional Chinese medicine(TCM) syndromes. Methods： A total of 98 cases of patients after surgery for thyroid cancer were randomly divided into the observation group and the control group， with 49 cases in each group. The control group was given oral administration of Levothyroxine Sodium Tablets，and the observation group was given oral administration of Levothyroxine Sodium Tablets and Yiqi Yangyin Decoction. The clinical effects in the two groups were compared. Before and after treatment， the thyroid function， the levels of β2- microglobulin(β2- MG) and interleukin- 6(IL- 6) in serum， and the TCM syndrome scores were compared between the two groups. Results：The total effective rate was 91.84% in the observation group，higher than that of 69.39% in the control group(P＜0.05). Before treatment， there was no significant difference being found in the comparison of levels of free friiodothyronine(FT3)，free throxine(FT4) and thyroid stimulating hormone(TSH) in serum between the two groups(P＞0.05). After treatment，the levels of FT3 and FT4 in serum in the two groups were increased(P＜0.05)，and the TSH levels were decreased(P＜0.05)；the levels of FT3 and FT4 in serum in the observation group were higher(P＜0.05)， and the TSH level was lower than those in the control group(P＜0.05). Before treatment， there was no significant difference being found in the comparison of levels of β2-MG and IL-6 in serum between the two groups(P＞0.05). After treatment，the levels of β2-MG and IL-6 in serum were decreased(P＜0.05)，and the levels in the observation group were lower than those in the control group(P＜0.05). Before treatment，there was no significant difference being found in the comparison of each TCM syndrome score between the two groups(P＞0.05). After treatment， the TCM syndrome scores in the two groups were decreased(P＜0.05)，and the scores in the observation group were lower than those in the control group(P＜0.05). Conclusion：Yiqi Yangyin Decoction has a good effect for patients after surgery for thyroid cancer. It can improve thyroid function and TCM syndrome scores，and reduce the levels of low molecular proteins and cytokines related to malignant tumors.