Objective To explore the application value of 18F-PET/CT imaging in periodic reviews in patients with thyroid carcinoma differentiation. Methods 45 patients with thyroid carcinoma differentiation who underwent 18F-FDG PET/CT examination in our hospital from January 2012 to June 2016 were enrolled in the study to carry out retrospective analysis, operation/follow up results were called a baseline, sensitivity and positive predictive value of 18F-FDG PET/CT were calculated. Results 18F-FDG PET/ CT examination found that 42 patients were positive imaging in 45 patients, sensibility was 93.3% (42/45). 105 cases of cervical lymph node metastasis, 9 cases of pulmonary lymph nodes, 6 cases of mediastinal lymph nodes were found in 45 patients, postoperative pathologic confirmed that 111 cases were tumor recurrence or metastasis, 9 cases were inflammatory disease, positive predictive value was 92.5%(111/120). Conclusion 18FFDG PET/CT imaging after postoperative large dose 131I treatment, Tg is increased, 131I-body scan results show that negative patients with thyroid carcinoma differentiation can avoid missed diagnosis effectively by the observation of tumor metabolism, periodic reviews can find out recurrence or metastatic lesions as soon as possible, and provide guidance for follow-up treatment, has significant clinical application value.