Objective To investigate the feasibility of combined 131I and Leucoge curing the differentiated thyroid carcinoma after operation and in order to enhance the therapeutic compliance and efficacy in the thyroid cancer patients during therapy period. Methods The information was collected and then had a retrospective analysis in 167 differentiated thyroid cancer patients with postoperative residual thyroid tissue, local recurrence or lymph node and systemic metastases. Total 167 patients were divided into 3 groups that was based on giving Leucogen tablets 20mg tid (Group A, n=47), 40mg tid (Group B, n=54) and 80mg tid (Group C, n=66) following post-treatment with 131I. The therapeutic effectiveness of 131I combined with Leucoge was evaluated during therapy period. Results There were no change between three groups in sample size, age, WBC and PLT before curing of 131I (P>0.05). The level of WBC and PLT in three groups had selective change after 131I treatment. The WBC and PLT levels in Group A and Group B had significantly decreased (P<0.05) and no effect in Group C (P>0.05). The efficacy of 131I on differentiated thyroid carcinoma with postoperative residual thyroid tissue, local and distant metastases was confirmed in this study. Conclusion The combination of 131I and Leucoge is an effective cure on postoperative differentiated thyroid carcinoma to prevent the decrease of WBC and PLT as well as bone marrow suppression.