Objective:To evaluate the activity of FORT on assessing ovarian response and predicting pregnancy outcome by FORT in IVF-ET. Methods:Three thousand and two hundred and nighty-two patients of controlled ovarian stimulation,divided into low,medium and high groups based on FORT,were investigated and each activated by rFSH 225 U. The controlled ovarian stimulation data of these patients and their laboratory index were analyzed. Results:Antral follicle count (AFC) is the lowest in the high FORT group and the highest in the low FORT group,preovulatory follicle count (PFC),as well as E2 with injection of HCG in the same day,are the highest in the high FORT group and the lowhest in the low FORT group. The number of retrieved oocytes,the total number of embryos and the number of high quality embryos escalate increased consistently with the FORT in these group,and the differences were significant amony group amparison comparison. Meanwhile,the embryo implantation rate and the clinical pregnancy rate also differ statistically in these groups and reach to the highest level in the high FORT group. Condusion:FORT is an important tool to study the reactivity of ovary. The high FORT group has better pregnancy outcome.