After the total excision of thyroid cancer, the TG, i.e. thyroglobulin, does not come down, and recurrence of metastasis is generally suspected. Thyroglobulin is an indicator to observe thyroid cancer after total thyroid cancer resection, generally after thyroid cancer surgery, normal thyroglobulin should be controlled below 1ng/ml, if it exceeds this range, it is suspected that the patient has recurrence and metastasis of thyroid cancer with a higher possibility. Thyroglobulin is a specific protein produced after total thyroidectomy and is secreted by thyroid epithelial cells. Serum thyroglobulin has high sensitivity and specificity in detecting recurrence and metastasis of thyroid cancer. If thyroglobulin remains high after total excision of thyroid cancer, patients should go to the hospital in time for follow-up examination to find out whether there is recurrence or metastasis, and if recurrence or metastasis is found, secondary treatment, such as iodine 131 treatment, should be carried out.