The thyroid gland is not graded, but is graded for nodules of unknown nature in the gland, divided into 5 classes. 4 classes are divided into 3 classes, such as class 4a, 4b and 4c. 1, Class 4a represents a certain possibility of malignancy, the risk of malignancy is below 30%, and the patient is clinically recommended to have intermittent follow-up for 3 months or fine needle aspiration biopsy. If the test result is negative, it is recommended to continue short-term follow-up. 2. 4b nodules indicate a greater risk of malignancy, and fine needle aspiration biopsy is preferred. 3. 4c nodules have a risk of malignancy between 60% and 95%, and surgical treatment is recommended. On top of them there are 5 categories of nodules that can be diagnosed as malignant thyroid nodules and immediate surgical treatment is recommended