Objective: To study the effect of nutritional support + intravenous chemotherapy on anti-tumor immunity and cancer cell proliferation in patients with colon cancer complicated by incomplete intestinal obstruction. Methods: Patients with colon cancer complicated by incomplete intestinal obstruction who were treated in Midi Branch, Pangang Group General Hospital between March 2015 and October 2017 were selected and randomly divided into the nutrition group who accepted nutritional support + FOLFOX4 intravenous chemotherapy and the control group who accepted FOLFOX4 intravenous chemotherapy alone, and they underwent surgery after two cycles of chemotherapy. The contents of immune cells in peripheral blood and the contents of immune cytokines in serum were determined before chemotherapy and two cycles after chemotherapy; the expression levels of proliferation genes in colon cancer lesions were determined after surgical resection. Results: Compared with those of same group before chemotherapy, peripheral blood Treg, Th9, Th17 and Th22 contents as well as serum IL-4, IL-9, IL-10, TGF-β1, IL-17 and IL-22 contents of nutrition group were decreased significantly after chemotherapywhereas peripheral blood Treg, Th9, Th17 and Th22 contents as well as serum IL-4, IL-9, IL-10, TGF-β1, IL-17 and IL-22 contents of control group did not change significantly after chemotherapy, and compared with those after chemotherapy between groups, peripheral blood Treg, Th9, Th17 and Th22 contents as well as serum IL-4, IL-9, IL- 10, TGF-β1, IL-17 and IL-22 contents of nutrition group were significantly lower than those of control group, and CyclinD1, Bcl-2, USP22, VEGF and N-cadherin mRNA expression were not different from those of control group. Conclusion: Nutritional support + intravenous chemotherapy can improve the anti-tumor immune response without affecting the proliferation of cancer cells in the lesion of patients with colon cancer complicated by incomplete intestinal obstruction.