Objectives: To investigate the positive effect of Th17 cells on the prognosis of patients with PTC and HT. Methods: The expression of nuclear specific marker RORγt of Th17 cells in fresh and paraffin thyroid tissues and serum specimens were analyzed. Flow cytometry was used to detect the formation rates of Th17 cells (CD3+CD8IL-17A+/CD3+CD8-%) at different time points after co-culture of thyroid papillary carcinoma cell line (TPC-1 and K1) and umbilical cord blood initial T lymphocytes. The protein expression of RORγt in T lymphocytes after co-culture was detected. Preoperative serum levels of Th17 (IL-17) cytokines were measured. Results: The positive expression of RORγt in the tumor microenvironment of PTC patients with or without HT could inhibit the lymph node metastasis of the tumor. PTC cancer cells could induce initial T lymphocyte to differentiate into Th17 cells, and the K1 cell line with lymph node metastasis induced a higher proportion of RORγt protein than that in TPC-1 cell line without lymph node metastasis. In PTC patients with HT, serum IL-17 concentration was negatively correlated with lymph node metastasis in the central group. Conclusions: RORγt may play an anti-tumor role in reducing thyroid cell damage by reducing the thyroid autoimmune antibodies TPOAb and TGAb in the PTC population in Yunnan plateau region. © 2018, E-Century Publishing Corporation. All rights reserved.