The thyroid nodule grade 2 or category 2 is one of the categories in the classification of thyroid nodules. Nowadays, thyroid nodules are basically classified into five categories according to the American College of Radiology classification criteria, namely ACR classification criteria, namely category 1, category 2, category 3, category 4 and category 5, mainly based on the characteristics of thyroid nodules. The ultrasound will evaluate whether the nodule is cystic or solid, whether the echogenicity is high or low, whether the shape is vertical or lying inside, whether there is calcification, whether the border is clear, and whether it is invading outside the envelope, etc. Each index will be scored. category 2 means that the total score is less than 2 after adding up the indexes, and basically the nodule is considered benign with less than 2% risk of malignancy. If there is no calcification, if the nodule is mainly cystic, or if the echogenicity is mainly hyperechoic, it can be considered as category 2, and basically there is no major problem.