To standardize the diagnosis of thyroid diseases, we have categorized thyroid nodules into six levels, with the severity and the likelihood of malignancy increasing with each level: Grade 1 refers to normal thyroid tissue; Grade 2 indicates benign changes in the thyroid, with the risk of malignancy increasing over time. For example, simple thyroid cysts, which require an ultrasound check every 1-2 years; Grade 3 refers to the presence of nodules in the thyroid with a malignancy possibility of <5%, commonly seen as cystic-solid nodules, requiring an ultrasound every 3-6 months; Grade 4 refers to the presence of nodules in the thyroid where it is difficult to distinguish between benign and malignant, with the overall malignancy risk ranging from 5-80%. At this stage, we recommend a fine needle aspiration biopsy for further classification. Grade 4 can be subdivided into Grade 4a and Grade 4b. Grade 5 indicates that nodules in the thyroid are mostly malignant, with the malignancy probability exceeding 80%, suggesting a biopsy or direct surgical treatment; Grade 6 indicates that the nodules have been biopsied and proven to be malignant. Typically, we consider thyroid conditions under Grade 3 as benign changes. Grades 4 and above are more often considered malignant. Patients with Grade 4 should actively cooperate with their doctors for appropriate management.