Abstract: Objective To research the effects of human chorionic honadotropin（hCG）on proliferation and cell cycle of papillary thyroid carcinoma. Methods The thyroid cancer cell line IHH-4 was involved in this experiment. Tetrazolium-based colorimetric assay (MTT) and flow cytometry (FCM) were used to test the effects of hCG on proliferation activity and cell cycle of IHH-4 at different concentration for 24,48 and 72 h, respectively. Results hCG could promote cell viability of IHH-4, significantly at the concentration of 100 IU/ml. Treated with hCG in concentration of 100 IU/ml for 48h, G2M+S phase of IHH-4 cells were 67.1%, significantly higher than control group. Conclusion Human Chorionic Honadotropin（hCG）could promote proliferation activity and accelerate cell cycle of papillary thyroid carcinoma cell.