Abstract: The authors reported a case of differentiated thyroid cancer (DTC) with multiple bone metastases after resection, whose ⁹⁹Tc^m-methylenediphosphonate whole-body bone scan was negative while ¹³¹I post-treatment whole body scan (Rx-WBS) was positive. This article clarified the characteristics of the disease from laboratory examinations, histopathological examinations and imaging examinations results. This case illustrated that ¹³¹I Rx-WBS was conducive to the discovery of DTC bone metastases, and ¹³¹I therapy has a significant effect.