Abstract: Objective To investigate the factors influencing the estrogen production of functional ovarian hyperandro genism.Methods 18 pat ients w ith functional ovarian hyperandrog enism(FOH)were divided into two groups according to the number of the fo llicles measuring 2~8mm in diameter,one group had 8 to 11 follicles together in two later al ov ar ies(named as FOHⅠ),and the ot her group had 12 to 24(named as FOH Ⅰ).Eight ovulatory females were recruited as controls.An ovary stimulation test with HCG and HM G was administered to evaluate the level o f testosterone and estradiol(E₂) in serum.T hen,the funct ional state and functional activity of aromatase were calculated.Results At the 3 hours point after the ovary excitation,the serum E₂ level of FOH Ⅰ was sig nificantly hig her than that of the contr ol g roup,while at the 8,12,18,24 hours point,the E₂ level of FOH Ⅰ was significantly higher than that of FOH Ⅰ.The functional state and functional activity of aromatase had no difference among the groups.Conclusion Both a high level of testosterone and a more number of follicle can increase the synthesis of estrogen after the ovary excitation test.The sensitivity of FOH ovary to the ovary excitation test is higher when the follicle number is more.