Abstract: Objective To study the effects of vitamin D₃ on steroidogenesis and secretion in vitro by chipped ovaries of rats.Methods Using orthogonal ex perimental design(L₁₆(4⁵)),two factor ial experiments were designed to explore the influence of four dosag elevels of vitamin D₃(0,10^-4,10^-7,10^-10mol/L)and four different stages(proestrous,estmus,postestrous,dioestrous)of estrous cycle on steroidogenesis in the ovary.Results In chipped ovary culture,effects of vitmin D₃ on estradiol secretion were significant(P<0.001),and effects of vitamin D₃ on progesterone secretion were not significant(P>0.05).Effects of estrous cycle on estradiol and prog esterone secretion were significant(P<0.001,P<0.05).Conclusion There is direct effects of vitamin D₃ on sex hormones secretion in intro by ovaries,and vitamin D₃ may be one of the environmental endocrine disruptors(EEDs).