The precautions for three years after thyroid cancer surgery are as follows:1. Pay attention to thyroid function: pay attention to the range of T3, T4 and TSH values, and whether there is hyperthyroidism or hypothyroidism, if hypothyroidism, thyroxine supplementation is needed.2. Pay attention to whether there is local recurrence and distant metastasis: local recurrence is mainly the result of localized thyroid lumps after thyroid cancer surgery, and CT biopsy should be done to find irregular or homogeneous thyroid lumps, and such metastatic lymph nodes should be combined with lymph node metastasis. Local recurrence is mainly due to the localization of thyroid lumps after thyroid cancer surgery, and irregular or inhomogeneous thyroid lumps are found by CT or magnetic resonance examination, and at the same time, there are lymph node metastasis, and if the metastatic lymph nodes undergo puncture biopsy and thyroid cancer cells are found, then it can be clearly defined as recurrence and metastasis. Three years after thyroid cancer surgery, one should also pay attention to whether there is any distant metastasis, such as lung metastasis, bone metastasis, liver metastasis, brain metastasis, which can be detected by CT or magnetic resonance examination of the corresponding parts.