Abstract: Colorectal cancer is one of most common malignant tumor of the gastrointestinal tract and it is difficult to early diagnosis. Rencently， with the development of screening for high-risk individuals and improvement of endoscopy， the early diagnosis of colorectal cancer has improved largely. However， those with obvious symptoms have developed into advanced stage and their prognosis was poor. Circulating cell-free DNA （cfDNA） as a new type of tumor biomarkers has been widely concerned recently. It has great potential for choosing chemotherapy regiems， evaluating therapeutic effect and predicting prognosis. In this paper， clinical utility of circulating cell-free DNA in colorectal cancer will be reviewed.