Abstract: Lymph node metastasis is reported in 20% to 65% of patients with differentiated thyroid cancer,among which 4% to 20% of patients have recurrence.Accurate diagnosis of metastatic lymph nodes is of great significance to the prognosis of patients.Fine needle aspiration biopsy is the gold standard for the diagnosis of metastatic lymph nodes,but it may lead to false negative results.Thyroglobulin detection in the washout after ultrasound-guided fine needle aspiration is complementation to fine needle aspiration biopsy,and the combination of them can significantly improve the accuracy of the diagnosis of metastatic lymph nodes.The progress of thyroglobulin measurement in the needle washout after ultrasound-guided fine needle aspiration in diagnosis of lymph node metastasis of differentiated thyroid carcinoma are summarized in this paper.