The invention provides a novel serum-free medium for inducing neural stem cells. The medium comprises a neural stem cell-induced medium, a neural stem cell proliferation culture medium and a neuronaldifferentiation medium, wherein the neural stem cell-induced medium consists of an animal basal culture medium N2G21 and neural induction compounds PD98059 and JW55; the neural stem cell proliferationculture medium consists of the animal basal culture medium N2G21 and a growth factor OsrbFGF; the neuronal differentiation medium is an N2G21 basal culture medium. The culture medium adopts a scientific design and a simple formula; compared with the prior art, the novel serum-free medium disclosed by the invention has the advantages that pure chemical molecules replace a protein signal antagonist; a non-animal original growth factor is used to replace a traditional animal original growth factor; neural stem cells which can self update and are differentiated into neuronal cells are obtained byhuman multipotential stem cell culture; in addition, the neural stem cells prepared by using the culture medium have higher clinical safety.