Abstract: OBJECTIVE To analyze the infection status of the surgical site of patients with colorectal cancer and the influencing factors of postoperative infection. METHODS The clinical data of 450 patients who underwent rectal cancer and colorectal cancer surgery from Jan. 2009 to Oct. 2016 were retrospectively analyzed. The status of infection in patients was observed, and the influencing factors of postoperative infection were analyzed. RESULTS There were 98 cases of infection among 450 cases of patients, and the infection rate was 21.78%. Among them, 43 cases of patients with colorectal cancer were infected, and 55 cases of patients with colon cancer infection were infected. There were 18 cases of perineal infection, and 80 cases of abdominal infection. There were 72 cases of superficial incision infection, 19 cases of deep incision infection and 7 cases of interstitial infection. A total of 114 strains of pathogens were isolated from 98 infected patients. Among them, there were 89 strains of gram-negative bacteria accounting for 78.07%, mainly Escherichia coli, and 25 strains of gram-positive bacteria accounting for 21.93%, mainly Staphylococcus aureus. Operative time, body mass index (BMI), combined with diabetes mellitus, and clinical stage were the related factors of surgical site infection in patients with colorectal cancer (P<0.05). CONCLUSION Colorectal cancer patients are prone to be infected at the operative site after operation. Gram-negative bacteria are the main pathogens. Positive intervention should be given according the risk factors of infection.