The environmental hormones have been mainly focused recently because of their wide existence and serious endocrine disturbing for humans and animals. The natural steroid estrogens (estrone, estradiol and estriol) released by both human and livestock are characterized by the strongest endocrine disturbance. The paper reviewed the animal excretion, physicochemical characters and potential risks on environment of the steroid estrogens. In addition, the behaviors of adsorption, degradation and transport of the steroid estrogens in the environmental media were summarized. On the basis of current studies on the estrogens, the tendency for the future research in this field was discussed and suggested.