Objective To analyze the application of the Galectin-3（Galectin-3） combined with free triiodothyronine（FT

3

）/free thyroxine（FT

4

） test in the differential diagnosis of benign and malignant thyroid nodules（TN）.Methods One hundred and thirty-nine patients with TN admitted to the Department of Thyroid Breast and Surgery of a hospital in Shangqiu City from January 2017 to June 2020 were selected as study subjects

of whom 47 subjects with malignant nodules and 92 subjects with benign nodules were diagnosed by postoperative pathology

which were included in the benign TN group（n=92） and malignant TN group（n=47）

respectively.The diagnostic value of Galectin-3 combined with FT

4

/FT

3

for the differentiation of benign and malignant TN was analyzed by comparing Galectin-3 and FT

4

/FT

3

in the 2 groups and plotting the receiver operating characteristic（ROC） curve.Results The FT3 levels of patients in the malignant TN group were lower than those in the benign TN group

and the percentage of positive Galectin-3 expression and FT

4

/FT

3

ratio were higher than those in the benign TN group

and the differences were statistically significant（P

<

0.05）.When Galectin-3 and FT

4

/FT

3

were used for differential diagnosis of TN separately

the AUC of Galectin-3 was significantly higher than that of FT

4

/FT

3

（P

<

0.001）

and the sensitivity and specificity of positive Galectin-3 expression for diagnostic differentiation of malignant TN were 91.49% and 89.13%

respectively.When Galectin-3 and FT

4

/FT

3

were used for combined diagnosis

the AUC values of Galectin-3 and FT

4

/FT

3

parallel tests were higher than those of tandem tests（P=0.002）

and the diagnostic sensitivity and specificity were 98.74% and 72.83%

respectively.Conclusion Galectin-3 single test has high efficacy in the differential diagnosis of benign and malignant TN

and its combination with FT

4

/FT

3

ratio in differential diagnosis can improve the sensitivity but decrease the specificity.FT

4

/FT

3

ratio and Galectin-3 tandem FT

4

/FT

3

ratio are of poor value in the differential diagnosis of benign and malignant TN.