Abstract: Colorectal cancer (CRC) is one of the most common types of cancer worldwide and the second leading cause of cancer-related death in the world. In recent years, the incidence of CRC has risen to the second place in China and more and more attention has been paid to its research. It has been found that the structure of intestinal flora is closely related to the occurrence and development of CRC. Probiotics, as a group of intestinal beneficial microorganisms, have the functions of regulating intestinal immunity, enhancing intestinal barrier and balancing of natural gut microflora. They play a significant role in the prevention and adjuvant therapy of CRC. This paper reviews the research progress on the effect of intestinal flora on CRC as well as the mechanism of probiotics on colorectal cancer, in order to lay a foundation for probiotics to prevent and alleviate CRC.