Clustered regularly interspaced short palindromic repeats associated RNA guided endonuclease Cas9 (CRISPR-Cas9) is a kind of adaptive immune defense system,which protects the bacteria or archaea against foreign genetic material.Type Ⅱ CRISPR-Cas system relies on Cas9 endonuclease that cuts exogenous DNA.Cas9 endonuclease targets and attacks the specific gene loci under the guidance of single guide RNA (sgRNA).CRISPR-Cas9 genome-editing technology has been widely used in different species.The application of CRISPR-Cas9 technology in stem cell research can greatly promote the generation of various genetically modified animal models from mammalians,such as mice,rats and primates,which can be used to identify the function of different genes at organismal level.Meanwhile,animal disease models can also be established efficiently,which can be applied to development of new treatment strategies.