Abstract: ¹⁸F-FDG PET and PET-CT has become an important tool in the postoperative management of de-differentiated thyroid cancer. But the value of this method in the preoperative diagnosis of thyroid nodules is unclear. Various groups of investigators have explored the potential role of ¹⁸F-FDG PET and PET-CT in patients with benign and malignant thyroid neoplasms expecially those with indeterminate fine needle aspiration cytology findings. With the increasing demand for ¹⁸F-FDG PET and PET-CT, clinicians are faced with the challenge of managing an increasing number of ¹⁸F-FDG PET and PET-CT detected thyroid incidentalomas because their significance remains unclear. The standardized uptake value of ¹⁸F-FDG is the most common semi-quantitive index and can be used to characterize malignant and benign thyroid nodules by describing the metablism of glucose. This article reviewed the value of SUV in differential diagnosis of malignant and benign thyroid nodules.