Abstract: Human gut microbiota is a complex microecological system, which is constituted by a large number of complex microbial communities and is closely related to human health and diseases. All kinds of microbes, interacting with each other, maintain the normal structure and functions of gut together such as intestinal digestion, absorption, metabolism of nutrients. Recently, multiple studies have showed that the gut microbiota plays an important role involved in the occurrence and development of colorectal cancer. In contrast,microecologics can be used for the prevention and adjuvant treatment of colorectal cancer by regulating the balance of gut microbiota. Here, this review elaborates the research progress on the relationship between gut microbiota and colorectal cancer and on the functions of the microecologies for screening, prevention and treatment of colorectal cancer, so as to provide some new idea for the diagnosis, prevention and treatment of the disease.