Growing lymph nodes again after thyroid surgery may be caused by recurrence of lymph nodes, metastasis, failure to remove them cleanly, or excessive intake of food containing iodine. 1. Thyroid lymph node recurrence and metastasis: Thyroid node recurrence is mainly caused by genetic factors, low autoimmunity, environmental factors, etc., so it is necessary to have a review on time after surgery. Metastasis will occur in middle and late stage thyroid lymphoma, and failure of timely detection or timely treatment will lead to the growth of lymph nodes again after thyroid surgery. 2. Thyroid lymph nodes are not cleanly removed: the lymph nodes may not be completely removed in the last operation, which may lead to the growth of lymph nodes after thyroid surgery. 3. Excessive intake of iodine-containing foods: Excessive iodine intake will lead to a significant increase in autoimmune inflammation of the thyroid gland, which may cause lymph nodes to grow again after thyroid surgery. Lymph nodes after thyroid surgery may also be caused by excessive secretion of thyroid stimulating hormone, ionizing radiation, etc. If the symptoms of lymph nodes after thyroid surgery persist, it is necessary to seek medical treatment.