Abstract: OBJECTIVE To screen the nutritional risk of patients with colorectal cancer and observe its impact on postoperative infection so as to provide guidance for prevention of the postoperative infection. METHODS A total of 206 patients with colorectal cancer who were treated in the hospital from Jan 2008 to Jun 2016 were enrolled in the study, then the nutritional risk of the participants was screened by using nutritional risk scale (NRS 2002), the enrolled patients were divided into the study group with 82 cases (no less than 3 points) and the control group with 124 cases ( less than 3 points) according to the NRS 2002, and the total incidence rate of postoperative infection and incidence rate of incision infection were observed and compared between the two groups of patients. RESULTS The total incidence rate of postoperative infection of the study group was 15.85%, significantly higher than 3.23% of the control group (P=0.003); the incidence rate of incision infection of the study group was 8.54%, significantly higher than 0.81% of the control group (P=0.015). The levels of red blood cells (t=3.395), albumin (t=3.352), prealbumin (t=5.834), hemoglobin (t=2.853), and BMI(t=4.124) were significantly lower in the study group than in the control group (P<0.05). Univariate and multivariate logistic regression analysis showed that increase of preoperative NRS score, decrease of BMI, and reduction of albumin level were the risk factors for the postoperative infection in the patients with colorectal cancer (P<0.05). CONCLUSION The incidence rate of postoperative infection is remarkably high in the colorectal cancer patients with the NRS score no less than 3 points. It is necessary to strengthen the enteral nutrition support of the colorectal cancer patients with the NRS score no less than 3 points.