Preoperative tests are the basis for thyroid surgery. Before thyroid surgery, patients will undergo a series of tests. The tests are divided into two main parts: routine examinations and thyroid examinations. Routine preoperative examinations: ① Hematological examination: blood routine, blood biochemistry, coagulation function, hepatitis B, syphilis, etc.; hematological examinations not only determine the patient’s basal blood status and whether the liver and kidney functions are normal, but also exclude infectious diseases from intraoperative infection. ② Chest X-ray and electrocardiogram: to assess the patient’s cardiopulmonary function and surgical tolerance. Thyroid surgery examination: ① Check thyroid function (T3, T4, TSH, etc.) and thyroid inflammatory antibodies, which only require blood sampling; ② Thyroid ultrasound: Ultrasound is an important examination of the thyroid gland. Since thyroid nodules are basically asymptomatic, the doctor palpates or the patient himself feels a small mass (small lump) in the neck to initially determine the presence of nodules; through ultrasound examination, the benignity or malignancy of the nodules can be initially determined. ③ Fine needle aspiration: fine needle aspiration will be performed after ultrasound suspects the thyroid nodule is malignant. The accuracy rate of fine needle aspiration of thyroid nodules is over 90%. Thyroid cancer is generally divided into three major categories: differentiated type (papillary and follicular carcinoma), undifferentiated type, and medullary carcinoma. Fine needle aspiration can confirm the diagnosis of differentiated thyroid cancer and undifferentiated thyroid cancer, while medullary carcinoma can only be confirmed through postoperative pathology. ④ Electronic laryngoscopy: Thyroid surgery may injure the laryngeal recurrent nerve, which innervates the vocal folds, so it is necessary to determine whether the vocal folds are intact before surgery. And the laryngoscope can be used to observe whether the tumor has invaded the nerve. If the nerve is damaged, it may affect the way of subsequent surgery. In addition to the preoperative examination, patients need to perform surgical posture training: pillows under the shoulders and head tilted back, practicing from short to long until they can hold it for 2 hours. This examination mitigates the postoperative discomfort caused by the patient being in one position for a long time during the operation. Many patients are suspicious of fine needle aspiration, fearing that it may cause tumor spread. However, fine needle aspiration is one of the most mature tests for thyroid disorders. Under ultrasound guidance, the puncture is accurately positioned, the puncture eye is small, and it does not cause much pain to the patient. However, even the most perfect technique can have complications. The puncture may cause local bleeding and needle tract infection in patients, but the incidence is small. Compared with the diagnosis of benign and malignant tumors, the advantages of post-penetration complications clearly outweigh the disadvantages. Widespread use of puncture can avoid unnecessary surgery.