Abstract: Objective: To study of the method about dissection, proliferation and differentiation of mesencephalic progenitor cells in vitro. Methods: Neurosphere method was used to expand the mesencephalic progenitor cell clones in vitro in 3% atmospheric oxygen. Striatal culture conditioned media was used to induce the mesencephalic progenitor cells differentiated into mature DA neurons. Results: The mesencephalic progenitor cells were successfully expanded in vitro using the epidermal growth factor （EGF） and fibroblast growth factor-2（FGF-2） in 3% atmospheric oxygen. Following incubation in differentiation media containing striatal culture conditioned media, up to 2% of the precursor cells converted into TH-immunoreactive （TH-ir） cells, which exhibited mature morphological and functional properties of dopamine neurons in culture. Conclusions: Dividing human mesencephalic precursor cells can be isolated and expanded in vitro in the presence of reduced atmospheric oxygen, and striatal tissue induces some of these cells into TH-ircells.