Abstract: The present invention provides a method of separating estrogen from placenta, which uses supercritical fluid technique to load the placenta powder of human body or sheep, pig, deer and other animals into an extraction tank. Under the operating conditions of preset pressure and temperature, supercritical solvent is added into the extraction tank to extract estrogen from placenta, so as to acquire de-estrogen placenta powder and placenta extract liquor. Under the same condition, the de-estrogen placenta extract liquor and supercritical solvent are added by a preset volume flow ratio into an adsorption tank. The estrogen in the placenta extract liquor is adsorbed by the adsorption tank to obtain de-estrogen placenta extract. It is then eluted with ethanol solution by gradient proportion to obtain purified natural estrogen.