Abstract: In the management of differentiated thyroid cancer, radioiedine (¹³¹Ⅰ) ablation of thyroid remnants and ¹³¹Ⅰ treatment of metastatic lesions are very important. To prepare for ablation or treatment, optimal level of TSH has to be achieved. Recombinant human thyretropin (rhTSH) has the same structure and biological activity as endogenous TSH. It can effectively elevate serum TSH level and it has tittle side effects, rhTSH can also avoid hypothyroid symptoms which are sometimes very serious if withdrawal of thyroid hormone therapy is carried out. However, in a number of cases, dedifferentiation is observed, giving rise to poor prognostic thyroid cancers that are refractory to conventional treatment. Several novel approaches for the treatment of dedifferentiated thyroid cancers have made great breakthroughs. For instance, isotretinoin redifferentiation therapy has entered Phase Ⅱ clinical trials.