Male germ-line stem cells (mGSCs) have the capability of self-renewal and latent capability of differentiation. mGSCs is the unique diploid immortal cell which can transfer genetic information to filial generation. The combination of transgenic technology and mGSCs heterotransplanting will supply new opportunities and paths to cloning animal, transgenic animal and gene therapy of some human hereditary disease. We studied the isolation and cultivation of mGSCs that were isolated and purified from 5-6 month old bovine fetal testis, new born bovine testis by adopting mixed enzymes digestion and different attaching velocities methods. The results showed that sertoli cells were indispensable to mGSC’s proliferation and differentiation in vitro. The sertoli cells in logarithmic phase have a significant effect on mGSC’s attaching, proliferation and differentiation. Co-culture with Sertoli cells, mGSCs differentiated to long sperm after 16 days. A preliminary system for mGSC’s inducing differentiation was established.