Abstract：Objective To evaluate the proportion of immune regulatory T cells in normal thyroid and GD thyroid. Methods The proportion of regulatory T cells (Tregs), T helper 1 (Th1) cells, Th2 cells in 20 normal thyroids and 9 thyroids of GD patients were analyzed by flow cytometry and then compared to the proportion in peripheral blood. Results In peripheral blood, normal thyroid and GD thyroid, the proportion of Tregs were 1.79±0.43%, 17.07±10.16%, 20.87±13.26%; the proportion of Th1 cells were 14.45±2.46%, 17.28±3.02%, 8.62±1.88%, and the proportion of Th2 cells were 1.44±0.31%, 1.78±0.55%, 6.87±3.27%. Compared to peripheral blood, the proportion of Tregs was significantly increased in normal thyroid and GD thyroid (P<0.01). Compared to normal thyroid, the proportion of Th1 cells significantly decreased (P<0.05) and the proportion of Th1 cells significantly increased in GD thyroid (P<0.01). Conclusion Tregs are abundant in thyroid tissue and there is an imbalance of Th1/Th2 cells in GD thyroid tissue.