Objective  To investigate the influence of preoperative nutritional rik on the quality of life colorectal cancer of patients , and to provide the strategy of clinical nutritional support therapy. Methods  150 patients with colorectal cancer were selected from June 2014 to June 2016 in the department of general surgery of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, and no nutritional support treatment was performed within 24 hours after admission. The nutritional status of patients with colorectal cancer was assessed by the European nutritional risk screening scale (NRS-2002). The patients were divided into two groups according to the score, namely, control group (less than 3 points) and study group (greater than or equal to 3 points) to compare the incidence of postoperative complications in two groups. The difference of life quality was compared  according to core scale QLQ-C30 of European Research and Treatment and the Organization. Results  According to the NRS-2002 score, 64 patients were  aasigned to study group (43%) and 86 patients were in control group (57%). The incidence of postoperative infection and anastomotic leak were higher in study group  than in control group (P<0.05). The significant differences were found in general health status, physical function, conggnitive function, fatigue and insomnia in patients with different nutritional status (P<0.05). But there was no significant differences in social function, emotion function, nausea/vomiting, pain, dyspnea, appetite loss, constipation, diarrhea and financial difficulties (P>0.05). Multiple linear stepwise regression analysis indicated that nutritional status of patients with colorectal cancer was the independent influence factor of life quality. Conclusion  Colorectal cancer patients with nutrition risk was closely associated with higher postoperative complications and quality of life declines. Therefore, it is necessary to strengthen preoperative nutrition support therapy in colorectal cancer patients with nutrition risk.