Abstract: Oncogene-induced senenscence (OIS) is defined as a stable proliferative arrest of normal cells upon overexpression of aberrant proliferative signals of oncogenes through MAPK and PI3K pathway. The molecular mechanism of OIS is associated with the formation of heterochromatin and DNA-damage check-point response. The markers of OIS including senescence-associated β-galactosidase and senescence-associated heterochromatin foci. With the growing recognization of OIS, the new models of tumor progression are emerging. The further investigations of the mechanism of OIS are of great significance to our understanding of the tumorigenesis and provide new ideas and methods of cancer treatment.