Estrogens　as　a　kind　of　steroidal　sex　hormone　are　widely　used　in　humans,　especially　quinestrol　(QS),　dienestrol　(DS)　and　norethindrone　(NET,　19-nor-17-alpha-ethinitestoster-one),　which　cannot　be　completely　degraded　after　application.　Steroidal　estrogens　at　low　concentration　pulling　into　environment　can　disturb　the　normal　biological　function　of　wide　life　and　thus　lead　to　great　threat　to　humans.　So　it　is　important　to　explore　its　degradation　mechanism　and　its　behavior　in　the　environment.　In　this　study,　we　investigated　the　oxidation　or　reduction　system　under　gamma　irradiation　for　reducing　estrogenic　activity　in　the　aqueous　solutions　as　well　as　degradation　kinetics,　its　by-products　and　yield　of　transformation　by　different　analytical　methods　such　as　GC　MS　and　HPLC.　Gamma　irradiation　could　effectively　degrade　estrogens　in　aqueous　solution.　The　degradation　reaction　of　estrogens　could　be　depicted　by　first-order　reaction　kinetics.　The　total　organic　carbon　of　solution　decreased　with　an　increasing　absorbed　dose　with　the　order:　quinestrol　＞　norethindrone　＞　dienestrol.　The　toxicity　of　the　three　estrogens　was　declined　after　irradiation.　Mono-　and　quadric-hydroxylated　intermediates　as　well　as　organic　acids　were　formed　after　gamma　irradiation.