The diagnosis and grading of thyroid nodules is clinically based on the thyroid ultrasound imaging performance, and the TI-RADS grading is commonly used nowadays. The higher the grade, the higher the degree of malignancy of the nodule, and the higher the possibility of considering thyroid cancer. The TI-RADS grading of thyroid nodules under ultrasound is from 0 to 6. Grade 0 is no nodule; grade 1 is negative, with a normal or postoperative thyroid gland; grade 2 is a benign nodule (cystic, solid, with regular morphology and clear margins); and grade 3 is mostly benign, with a malignant risk of <2%. Grade 4 nodules have a malignancy likelihood of 2 to 90%, with 1 to 4 malignant signs (low/very low echogenicity, substantial, fuzzy border/microfollicularity, microcalcification, aspect ratio >1), and are divided into 3 subgrades; Grade 5 has a malignancy likelihood of >90%, with more than 4 malignant signs, and can be combined with cervical lymph node metastasis; Grade 6 is a pathologically confirmed malignant nodule. Thyroid nodules should be diagnosed and treated in a timely manner in order to avoid delays.