Abstract: Objective:To explore the influence of erythropoietin (EPO) on the proliferation and differentiation of neural stem cells (NSCs) in hypoxia.Methods:The NSCs were put into the incubator with of 10% O₂,and EPO was added into the cultures during the proliferation and differentiation period of NSCs.The proliferation of NSCs was evaluated by MTT method and clone calculation.After the differentiation of NSCs with 10% fetal bovine serum (FBS),the differentiation ratio of NSCs into neurons and glia cells was detected by immunocytochemistry for neuron-specific enolase (NSE) and glia fibrillary acidic protein (GFAP).Results:The cells cultured were nestin positive;after differentiation,part of them were NSE positive and others were GFAP positive.The cloning efficiency of NSCs in normoxia and hypoxia group was (32.26±3.26)% and (48.93±4.34)% respectively.The cloning efficiency in the condition of EPO with hypoxia increased by 17.26% compared with that of the hypoxia group,and NSE positive cells increased significantly during differentiation.Conclusions:The proliferation of NSCs is promoted in the condition of hypoxia and differentiated into neurons;hypoxia can increase the proliferation of EPO and induce them to differentiation of more neurons.