Objective To analyze the expression of Th1/Th2 and Fas/FasL in peripheral blood of patients with toxic diffuse goiter(Graves disease)before and after 131I treatment.Methods Sixty Graves patients diagnosed in Pingxiang People′s Hospital from January to December 2016 were selected as the observation group,and 60 healthy subjects were selected as the control group during the same period.All patients in the observation group received 131I treatment for the first time,and were divided into remission group(54 cases)and recurrence group(6 cases)according to the curative effect after 12 months of follow-up. The changes of Th1/Th2 migration and Fas/FasL expression in peripheral blood of patients before and after treatment were compared. Results Interleukin-12 (IL-12), interleukin-10 (IL-10), IL-12/IL-10 in the observation group were higher than those in the control group, IL-10 in remission group was higher than control group, IL-12、IL-10 in recurrence group were higher than those in the control group, the differences were statistically significant (P＜0.05). There were no significant differences in IL-12, IL-10, IL-12/IL-10 between the recurrence group and the observation group(P＞0.05). Fas and FasL in the observation group were higher than those in the control group, Fas in remission group and recurrence group was higher than that in control group, the differences were statistically significant (P＜0.05). Fas in remission group was lower than that in observation group and recurrence group, the difference was statistically significant (P＜0.05). There were no significant differences in Fas and FasL between the recurrence group and the observation group (P＞0.05). Conclusion After treatment, the immune response of recurrent Graves patients tended to be more Th1,and Fas level increased with the development of Graves disease. It is indicated that curative effect can be assessed according to clinical manifestations combined with the trend of helper T cells and test results of Fas.