Abstact:With the development of materials science and combination with medicine, more and more nano-materials are used in clinical medicine.There are much advantage in nano-material .The reason that the nano-materials are utilized widely is its quantum effect and huge superficalarea.But with further research ,more and more disadvantages are found. Many research on the environmental and human health risks of engineered nano-materials focus on their acute toxicity. However,the long-term chronic effects of nanomaterials on living systems is neglected.The potential of nanomaterials to promote the formation of reactive oxygen species is one of the primary reason in their genotoxic. DNA would be damaged by the reactive oxygen species. If the DNA cannot be renew ,it could lead to gene mutation , canceration. This review focuses on the impact of carbon-based nano-materials on DNA .