Objective: To investigate the clinical value of perioperative use of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) in patients undergoing radical surgery for colon cancer. Methods: Ninety-seven patients undergoing radical surgery for colon cancer in Gansu Provincial Hospital from February 2014 to February 2015 were selected and randomly designated to observation group and control group. Patients in observation group received ω-3 PUFAs combined with conventional intravenous nutritional support and control group received conventional intravenous nutritional support only during perioperative period. In these patients, the serum nutrition indicators and tumor markers were detected before and after surgery, and serum inflammation indicators as well as immune regulatory molecules in the serum and surgical specimens were determined after surgery. Results: The levels of serum nutrition indicators that included transferrin, prealbumin, retinol conjugated protein, insulin-like growth factor 1, hemoglobin and nutritional risk index, and the tumor markers that included CEA, CA19-9, CA125 and CA74-2 all showed no significant difference between the two groups (all P>0.05), but all the nutrition indicator levels were significantly better in observation group than those in control group on preoperative day 1 and postoperative day 3, and all the tumor marker levels in observation group were significantly lower than those in control group (all P<0.05). On postoperative day 3, the serum levels of proinflammatory factors that included IL-1, IL-6, IL-8 and TNF-α were significantly lower and the level of anti-inflammatory factor TGF-β was significantly higher in observation group than those in control group (all P<0.05); the levels of tumor metastasis promoting immune molecules that included CD44, CD168 and CD133 were significantly lower while the tumor metastasis promoting immune molecule CD63 was significantly higher in the tumor tissue in observation group than those in control group (all P<0.05). Conclusion: Perioperative use of ω-3 PUFAs in patients undergoing radical surgery for colon cancer can effectively improve their nutritional status, reduce postoperative inflammatory response, and enhance the immune function and anti-tumor ability.