Abstract: Differentiated thyroid cancer (DTC) patients always holds a good prognosis under standard surgery, selective ¹³¹I therapy and TSH suppression therapy. The goals of ¹³¹I therapy are characterized as remnant ablation, adjuvant treatment, and treatment of known disease, which are supposed to refine initial staging, facilitate follow-up, decrease recurrence, and improve disease-specific survival. However, there are still many issues to be clarified in clinical practice. For example, in the assessment of postoperative disease status before ¹³¹I therapy, it is difficult to estimate subclinical lesions, and there is no Tg threshold to guide ¹³¹I therapy, which makes the decision of adjuvant treatment even harder. In the follow-up, there is no uniform response criterion for ¹³¹I therapy in structural disease, the presence of TgAb will interfere with the judgement of disease status; ¹³¹I cumulative dose-related complications also need to be monitored and managed. This issue contains several articles related to the ¹³¹I treatment of DTC patients, discusses the difficulties in current ¹³¹I treatment and the explorations of Chinese scholars in several aspects.