Objective To analyze the variation of intestinal microflora in patients with colorectal cancer by SYBR GreenⅠreal-time fluorescence quantitative PCR and reveal the role and significance of intestinal microflora in the colorectal cancer-associated molecular pathogenesis. Methods A set of 16S rRNA gene group of species-specific primers for Bifidobacterium spp., Lactobacillus group, Escherichia coli, and ddl gene-targeted species-specific primers for Enterococcus faecalis and feces Enterococcus were designed. Patients with colorectal cancer (colorectal cancer group, n=30) and healthy volunteers (normal control group, n=30) were included and whose feces were collected to extract bacterial genome DNA. SYBR GreenⅠ real-time fluorescence quantitative PCR was used to analyze the five mentioned bacterial amounts. Results Level of Bifidobacterium spp. (4.52±0.49) and Lactobacillus group (5.46±0.12) in colorectal cancer group were significantly lower than those （9.25±0.83 and 7.45±0.37） of normal control group (Plt;0.05), whereas levels of Escherichia coli (5.82±0.47), Enterococcus faecalis (10.6±0.30) and feces Enterococcus (5.74±0.16) in colorectal cancer group were significantly higher than those （4.68±0.32, 4.95±0.24, and 5.03±0.43） of normal control group (Plt;0.05). Conclusions The fecal microflora composition of patients with colorectal cancer is significantly decreased in Bifidobacterium spp. and Lactobacillus group, whereas increased in Escherichia coli, Enterococcus faecalis, and feces Enterococcus. These data underline that the occurrence and progress of colorectal cancer may be related to intestinal microflora.