Radioiodine refractory (RAIR) is the major cause of thyroid cancer-related death. In order to avoid needless Radioiodine (RAI) therapy, recognizing the RAIR cases in time is important for the patients to obtain more time for the effective therapy. Evaluate the ultrasound features of cervical metastatic lymph node in patients with RAIR differentiated thyroid cancer (DTC). Seventeen adult patients with histologically confirmed locally advanced or metastatic RAIR-DTC were prospectively enrolled. The ultrasound (US) characteristics of cervical lesions in patients with the RAIR-DTC were compared with cervical lymph node metastasis from 59 non RAIR-DTC cases. Among the 17 patients, cervical lymph node metastasis was found in 15 patients (88.3%). The cervical lesions of RAIR-DTC (mean size, 2.0cm) were larger than that in non RAIR-DTC group (mean size, 1.30 cm). More multiple lesions and more lesions with visible flow were found in the RAIR Group, while fewer hyperechogenic punctuations were found in RAIR group (P<.05). The distant metastasis rates showed that RAIR-DTC led to a poorer prognosis than those of patients in the non RAIR Group (P<.01). Ultrasound can help distinguish metastasized cervical lymph nodes of RAIR-DTC patients from non RAIR-DTC patients. For RAIR-DTC patients, a long-term US evaluation should be performed.