The aging of the population is a global challenge. The number of older adults is rapidly growing, leading to an increase in the prevalence of noncommunicable diseases associated with aging, such as cancer. Almost two-thirds of all new cancer diagnoses are over 65 years, and this proportion is projected to increase globally. Cellular senescence is a state of stable growth arrest induced by DNA damage or dysregulation of oncogene, coupled with the morphological, biochemical, and epigenetical changes. Increasingly evidences have demonstrated that cell senescence might be an important mechanism for suppressing tumorigenesis. Recently, however it has become apparent that this process entails more than a simple cessation of cell growth, cellular senescence might also promote cancer progression. Which leading to the concept that cellular senescence can play as a double-edged sword in the fight against cancer. Therefore, in depth understanding of the relationship between cell senescence and tumor, and making full use of the antagonize effect of cellular senescence on tumor and avoiding its role in promoting the tumor may give us another potential choices for tumor therapy.