Colorectal cancer, with increasing prevalence year by year, is one of the most common encountered cancers with great threaten to people’s health. Recently, much evidence showed that the intestinal dysbacteriosis might play important roles in the pathogenesis of colorectal cancer through various various, including genetic changes in intestinal epithelial cells, inflammatory response of intestinal mucosa, and microenvironment disorder of intestinal tract. Many researches reported that some special microbiological species were found to be essential in the incidence of colorectal cancer, including Clostridium coccoides, Streptococcus bovis biotype I, Enterotoxigenic Bacteroides fragilis (ETBF), invasive Escherichia coli, human papillomavirus (HPV), and so on. In this paper, we reviewed the great significance and specific mechanisms of intestinal microbiota in the pathogenesis of colorectal cancer.