Abstract: Objective To observe the effects of adrenocorticotropin(ACTH) and testosterone(T) on erythropoiesis in mice with chronic hypoxia.Methods The mice with had been kept in hypobaric chamber(0.42atm,22h/d,9days),were administered erythropoietin(EPO,200u/kg·d,ip),ACTH(2.5u/d,sc),T(2.5mg/d,im),cortisol(0.5mg/d,sc) respectively,examined the level of serum EPO and hematocrit(Hct).Results The erythropoiesis of bone marrow were very sensitive to the EPO stimulus early,sensitivety decreased gradually by EPO treatment during countinously hypoxia.As compared with simply hypoxic group simultaneously,the Hct could be markdly increased by ACTH or T(it did not caused by cortisol),but the serum EPO did not elevated respectively.Conclusion Evoked effects on erythropoiesis exist in mice with chronic hypoxia by ACTH or T treatment.