Thyroid nodule grade 5 is a grade under thyroid ultrasound. thyroid nodule grade 5 is highly suspicious for malignancy, with a >90% likelihood of malignancy and is more serious. The TI-RADS classification is a risk assessment of the benign and malignant nature of thyroid nodules based on imaging such as thyroid ultrasound. grade 5 is highly suspicious for malignancy and has a >90% likelihood of being a malignant nodule such as thyroid cancer, and is therefore more serious. Grade 5 thyroid nodules >10mm or >5mm adjacent to the trachea and the laryngeal nerve require puncture biopsy to further define the nature of the nodule, while ≤10mm and ≤5mm nodules adjacent to important structures such as the trachea can be selected for puncture biopsy according to the patient’s level of anxiety and willingness to undergo biopsy. If thyroid cancer is serious, there is a risk of invasion of surrounding tissues and metastasis if not treated in time, and radical surgery, radionuclide, thyrotropin suppression and other treatments are needed. Among the thyroid cancers, papillary and follicular cancers have a better prognosis and are not very serious if treated in time, while medullary and undifferentiated cancers have a worse prognosis and are more serious. If it is benign thyroid disease, it is generally not serious, symptomatic treatment and regular follow-up observation are enough. It is recommended that patients with grade 5 thyroid nodules should consult a doctor for further examination and treatment as prescribed by the doctor.