In clinical practice, we often encounter patients who need to undergo reoperation for thyroid cancer recurrence after surgery. Some of them are short-term recurrences, and swollen lymph nodes in the neck are found a few months after surgery; some of them have malignant nodules growing in the residual thyroid gland a few years after surgery, or swollen lymph nodes with metastasis in the neck. This on the one hand increases the psychological burden and mental pressure of the patient, and on the other hand makes the patient suffer from the trauma and pain of the organism, and at the same time increases the economic burden! Through clinical observation, summary and analysis, we found that there are several reasons for the recurrence of thyroid cancer after surgery as follows: 1. The first surgery method is not standardized and not complete. There are many doctors doing thyroid cancer surgery, such as general surgery, ENT, hepatobiliary surgery and breast surgery, but not many of them can really do it in a correct, standardized and thorough way. Many patients’ recurrence after surgery is related to many doctors who are not specialized enough. Some patients should have undergone total thyroidectomy, but only unilateral lobe + isthmus + contralateral most or sub-total resection was done, leaving a part of it, which leaves a hidden problem, then it is easy to recur; some patients should have undergone lymph node dissection in neck area VI and VII, but it was not done, which leaves a root of trouble, and it is very easy to have lymph node recurrence after surgery; some patients have incomplete lymph node dissection in side neck or no lymph node dissection at all, then recurrence is inevitable. In some cases, the lateral cervical lymph nodes are not completely cleared or not cleared at all, so recurrence is inevitable. The errors of the above surgical methods are the main reasons for recurrence in clinical practice. Therefore, it is crucial that the first surgery is standardized, correct and thorough! 2.Iodine 131 treatment was not performed or could not be performed after surgery. The treatment of thyroid cancer requires comprehensive treatment, and post-operative iodine 131 treatment is one of them. Some patients need this treatment after surgery in order to completely kill cancer cells and achieve the purpose of radical cure. However, some surgeons only know about surgery, but do not know the indications of postoperative iodine 131 treatment, so they do not inform the patients, which causes the patients to lose the time to have this treatment, and when the metastatic lymph nodes in the neck are found, it will be too late. Or if the patient is not undergoing total thyroidectomy, there is still residual thyroid tissue, but the patient is asked to perform iodine 131 treatment, which is ineffective; even if this treatment is performed, it is useless. 3.Postoperative management is not in place. Thyroid cancer patients should take levothyroxine tablets (commonly used as euthyroxine) for life after surgery, and thyroid stimulating hormone (TSH) should be controlled to reach the standard range to inhibit and reduce recurrence; however, it is found in the clinic that some patients cannot adhere to the medication, which leads to recurrence, and some doctors cannot properly guide patients to take the medication to reach the standard, which leads to recurrence. Therefore, patients should regularly check thyroid function and related indicators, and regularly perform thyroid ultrasound to detect early signs of recurrence and deal with them early. 4. Post-operative diet is not controlled. Post-operative thyroid cancer patients should have low iodine diet, which can also lead to cancer recurrence if they do not pay attention to control. They should eat non-iodized salt, not to eat sea vegetables with high iodine content such as kelp, nori and wakame, and try not to eat fish and shrimp, scallops, crabs and clams from the sea, but can eat freshwater fish and shrimp, etc. Only in this way can the chance of cancer recurrence be reduced. In conclusion, the recurrence of thyroid cancer after surgery is multifaceted, but it is absolutely related to the way of the first surgery! That’s why it is wise to choose a specialist and a skilled and proficient surgeon!