Thyroid nodule category 4B is an ultrasound classification. 4B nodules are moderately suspected of malignancy, with a 10% to 50% malignancy rate. 4B thyroid nodules are usually recommended to undergo fine needle aspiration of the thyroid gland to clarify the nature of the nodule. Benign asymptomatic nodules can be followed up for observation, and surgical treatment is needed when there are compression symptoms or malignant tendency. For category 4B thyroid nodules, puncture is recommended if the nodule is >10mm; if the nodule is adjacent to the peritoneum, trachea, or laryngeal reentrant nerve, or if the nodule is multifocal, then puncture can be considered when it is >5mm. Whether biopsy is needed for nodules <5 mm immediately adjacent to the peritoneum, trachea, or recurrent laryngeal nerves or multifocal nodules requires consideration of the biopsy surgeon's surgical skills and the patient's level of anxiety; for unifocal nodules ≤10 mm, if they are not immediately adjacent to the peritoneum, trachea, or recurrent laryngeal nerves, an active surveillance strategy can be chosen with full informed consent. Patients with thyroid nodule category 4B should consult a medical professional for consultation.