Objective: To observe the protective effect of Elk antlers ethanolic fluidextract(EAEF) on gonad function impairment of male mice induced by cyclophosphamide(CP). Methods: The model of gonad function depression was prepared by repeatedly intraperitoneal injection of CP. Low and high dose of EAEF were given to mice with oral administration to intervene this process,then the level of testosterone and luteinizing hormone in serum were detected;the weight index of sex organ and accessory sex organ were observed;sperm density and sperm activity were detected;the superoxide dismutase (SOD) activity and malonaldehyde(MDA) content were measured. Meanwhile the histopathological changes in testis were observed by light microscopy. Results: EAEF reversed the decline of testosterone and luteinizing hormone level in serum,enhanced the testicle mass index,sperm density and sperm activity,increased SOD activity and decreased content of MDA in testis,as well alleviated the histologic pathological formation in testis in cyclophosphamide-induced model mice. Conclusion: EAEF has protective effect on gonad dysfunction impairment of male mice induced by CP,which might be related to its the gonadotropin hormone-like effect and antioxidation.