Thyroid nodules are diseases in the thyroid parenchyma that are distinguished using ultrasound or/and radiographic methods. Due to the widespread use of high-performance ultrasound, their prevalence is as high as 19-69%, with the vast majority of them being benign lesions, mostly nodular goiter or thyroid tumors, but 5%-10% being malignant lesions. After thyroid nodules are detected, the most important thing is to evaluate their benignity and malignancy, which relies mainly on ultrasound. Ultrasonography can show the size, number, shape, location, internal structure, boundary, blood flow and the presence of calcification of nodules. It should be emphasized that specialized ultrasound examiners and experienced clinicians can achieve a high level of diagnostic accuracy based on ultrasound examination reports combined with some laboratory results. Most benign nodules do not require medication if malignant lesions can be ruled out, except for some Hashimoto’s thyroiditis and hyperthyroidism, which require medical medication, and most nodules require regular review (1-2 ultrasound exams per year), and some larger nodules (larger than 3-4 cm) also require surgery.