Abstract: Cerium oxide nanoparticles(CNPs) are widely investigated in biomedical field due to their potent regenerative anti-oxidant properties. CNPs can protect normal cells from oxidative damage to prevent the development of diseases that are related to the dysregulation of reactive oxygen species levels, such as cancer, et al. In cancer treatment, CNPs exhibit cytotoxicity, and can modulate tumor microenvironment to repress tumor invasion. In combination with radiotherapy, CNPs can be used as both radiosensitizers and radioprotective agents to enhance the efficacy of radiotherapy and reduce adverse reactions. In addition, CNPs are promising vectors in targeted drug delivery. This review summarizes the application of CNPs in cancer prevention and treatment and its correlated mechanisms, in order to provide useful information for further research and clinical application of CNPs.