Objective: The aim of our study was to investigate the correlation between the expression of sodium/iodide symporter, serum levels of β2-MG and prognosis of thyroid carcinoma patients. Methods: Ninty-five cases with thyroid carcinoma, using enzyme-linked immunosorbent assay with double-antibody sandwich to detect the serum β2-MG levels and immunohistochemistry to detect NIS expression of thyroid cancer tissue. Results: Thirty-seven cases showed positive expression of sodium/iodide symporter (38.9%) and 30 cases showed positive expression of β2-MG (31.57%). There were significant differences of NIS expression (χ2=8.207, P=0.017) and β2-MG expression (χ2=10.121, P=0.006) between different pathological types of thyroid carcinoma, but there was no correlation between the positive rate of the two research groups (r=-0.546, P=0.633). The significant differences was observed in expression of sodium/iodide symporter (χ2 = 9.272, P=0.002) and expression of β2-MG (χ2=4.441, P=0.035) between the group with neck lymph node metastasis and the group without neck lymph node metastasis and both positive rate was significantly negatively correlated (r=1.000, P=0.000). The significant differences was observed in expression of sodium/iodide symporter (χ2=9.272, P=0.002) and expression of β2-MG (χ2 = 3.867, P=0.043) between the group with distant organ metastasis and the group without distant organ metastasis (χ2=11.985, P=0.001) and both positive rate was significantly negatively correlated (r=-1.000, P=0.000). Conclusion: There are significantly negatively correlated between neck lymph node metastasis, distant organ metastasis and expression of sodium/iodide symporter and expression of β2-MG. Thyroid cancer lymph node and distant organ metastasis, the tumor tissue NIS expression and serum levels of β2-MG is significantly negatively correlated. The detection of serum β2-MG provides clinical reference value for the effects on radionuclide therapy and prognosis assessment of thyroid carcinoma. Serum β2-MG levels is negatively correlated with prognosis in thyroid cancer patients. Objective: The aim of The study was to investigate the correlation between the expression of sodium / iodide symporter, serum levels of β2-MG and prognosis of thyroid carcinoma patients. Methods: Ninty-five cases with thyroid carcinoma, using enzyme-linked immunosorbent assay with double-antibody sandwich to detect the serum β2-MG levels and immunohistochemistry to detect NIS expression of thyroid cancer tissue. Results: Thirty-seven cases showed positive expression of sodium / iodide symporter (38.9%) and 30 cases showed positive expression of β2 There was significant difference of NIS expression (χ2 = 8.207, P = 0.017) and β2-MG expression (χ2 = 10.121, P = 0.006) between different pathological types of thyroid carcinoma, but there was no correlation The significant differences were observed in expression of sodium / iodide symporter (χ2 = 9.272, P = 0.002) and expression of β2-MG (χ2 = 4.441, P = 0.035) bet ween the group with neck lymph node metastasis and the group without neck lymph node metastasis and both positive rate was significantly negatively correlated (r = 1.000, P = 0.000). The significant differences was observed in expression of sodium / iodide symporter (χ2 = 9.272 , P = 0.002) and expression of β2-MG (χ2 = 3.867, P = 0.043) between the group with distant organ metastasis and the group without distant organ metastasis (χ2 = 11.985, P = 0.001) and both positive rate was significantly negatively correlated (r = -1.000, P = 0.000). Conclusion: There are significantly negative correlated between the neck lymph node metastasis, distant organ metastasis and expression of sodium / iodide symporter and expression of β2-MG. Thyroid cancer lymph node and distant organ metastasis , the tumor tissue NIS expression and serum levels of β2-MG is significantly negatively correlated. The detection of serum β2-MG provides clinical reference value for the effects on radionuclide therapy and prognosis assessmen t of thyroid carSerum β2-MG levels are negatively correlated with prognosis in thyroid cancer patients.