Objective　To investigate the relationship between nitric oxide (NO) secreted by ovarian granular cell and interleukin-1β (IL-1β), and their functions in estrogen synthesis. Methods　The human ovarian granular cells recovered from follicular fluid were cultured with IL-1β or NO donor. Results　The quantity of NO cultured with or without IL-1β addition were (537±23) μmol/L、(411±15) μmol/L respectively. The former was significantly higher than the latter (P<0.01). The estradiol, progesterone synthesis and aromatizing enzyme activity in the media with the addition of NO donor were (1 234±136) μg/L、(988±103) μg/L、(0.422±0.052) Ci/ml, while as they were (1 792±103) μg/L、(2 486±123) μg/L 、(0.833±0.012) Ci/ml, in the media without the addition of NO donor. The estradiol progesterone synthesis and aromatizing enzyme activity in the media with NO donor decreased significantly as compared with the group without NO donor (P<0.01, P<0.001, P<0.01). Conclusions　Ovarian granulosa cells may secrete NO, and the secretion may be regulated by IL-1β. They may be involved in the ovulation at the preovulatory stage and regulation of ovary steroids synthesis.