TSH is thyrotropin, which is actually specified in the 2012 guidelines for the treatment of thyroid nodules and differentiated thyroid cancer developed by Chinese medical experts. With low thyroid function and compensatory elevation of TSH after thyroid cancer surgery, post-operative thyroid cancer patients should take eugenol for a long time. There are two main purposes: firstly, part of thyroid gland is removed after thyroid cancer surgery and thyroxine level is not enough, so it is necessary to supplement part of the hormone by taking the drug; secondly, taking Eugenol can lower TSH, and low TSH can control thyroid cancer recurrence, and the dose of oral Eugenol is chosen according to the risk level. The low risk of recurrence group often meets the following conditions, i.e. no local or distant metastasis, all visible tumors are cleared, tumors do not invade surrounding tissues, tumors are not of invasive histological type and there is no vascular invasion, whole body iodine 131 imaging after nail clearance, no iodine uptake in the thyroid bed and beyond. In the intermediate risk group, the following conditions must be met, i.e., soft tissue invasion around the thyroid gland can be found microscopically after the initial surgery, there are lymph node metastases in the neck, the tumor is an invasive histological subtype, the tumor invades blood vessels, and there is iodine uptake outside the thyroid bed on the systemic iodine 131 image after nail clearance. In the high-risk group, tumor invasion of surrounding tissues or organs was visible to the naked eye, tumor was not completely removed, tumor residual after surgery, distant metastasis, serum thyroglobulin level was still high after thyroidectomy, family history of thyroid cancer, and other conditions. TSH was less than 0.1mU/L in the recurrent intermediate and high risk group 1 year after surgery; the recurrent low risk group looked at drug risk, 0.1-0.5mU/L for those with small drug side effects and 0.5-1mU/L for those with large side effects, and the category to which the patient belonged was assessed again 1 year after surgery. Patients with high risk of recurrence who also have low risk of medication have TSH less than 0.1mU/L, but the TSH control target can be adjusted to 0.1-0.5mU/L if patients develop adverse thyroid hormone treatment. patients in the low risk of recurrence group with adverse drug reactions are recommended to control TSH to 0.5-2.0mU/L, and if patients develop adverse treatment reactions, the TSH control target can be adjusted to 1 -2mU/L.