Malignant tumors pose a major problem in public health across the world, threatening human health and socioeconomic development. Colorectal cancer (CRC) is more common in economically developed areas. In recent years, its incidences have been rising in some low-risk countries due to changes in dietary habits and lifestyle. Based on the findings in pertinent literature both at home and abroad, this article reviews the risk factors of colorectal cancer in four aspects:social demography, medical sciences, behaviors and lifestyle, and diet.