Serological thyroid hormone tests, diagnostic ultrasound, thyroid fine needle aspiration cytology and other related nuclear tests. Ultrasonography is important for the diagnosis and differential diagnosis of thyroid nodules. It can clarify whether the thyroid nodule is solid, cystic or mixed type, and the diagnosis rate is 95%. Ultrasound images with high resolution can analyze nodules down to 1mm lesions. The nature, size, number, location, morphology, margins, echogenicity and presence of calcified spots, the presence and characteristics of blood flow signals around and within the nodule, and the enlargement and morphology of the cervical lymph nodes are clarified by ultrasonography. When a solid nodule with irregular morphology, poorly defined borders, mixed echogenicity, dense irregular microcalcifications within the nodule, obvious halo around the nodule, abundant blood flow in the nodule and predominantly internal blood flow, and enlarged cervical lymph nodes are found, the nodule is more likely to be malignant and surgery is preferred. Fine needle aspiration cytology biopsy is the most direct and effective way to diagnose benign and malignant thyroid nodules. If the patient has enlarged lymph nodes, paralysis of the recurrent laryngeal nerve, destruction of thyroid cartilage or other laryngeal cartilage, it can be concluded that the nodule is malignant.