Embryonic stem cell (ESC) is a kind of stem cell with self-renewal capability and developmental luripotency,which is at the early stage of embryonic development,and it is the original cell of various kinds of tissue and organ.Under certain conditions,ESCs can maintain an undifferentiated state,long-term surviving and infinite breeding state in vitro.The research of tberapeutic effect of ESCs in animal disease model,especially in ouse,has made great progress.On the basis of this research,researchers attempt to use ESCs for the clinical therapy of various diseases,and investigate the feasibility and security of this kind of therapy.Currently ESCs have been used in the therapy of diabetes mellitus,Parkinson's disease and cardiovascular injury.Even though many problems of technique and ethics should be done,we believe that ESC therapy will be a promising method and used in linical practice if we make clear the mechanism of ESC directional differentiation,establish an optimal culture system,and solve the problem of oncogenicity.