Abstract: OBJECTIVE To observe the influence of enteral nutrition support therapy on prevalence of infections and immune function of the ICU patients of surgery department so as to provide guidance for the enteral nutrition support therapy. METHODS A total of 68 ICU patients of surgery department who were treated in the hospital from Dec 2015 to Jan 2017 were recruited as the study objects and divided into the control group (the parenteral nutrition group) with 34 cases and the observation group (the enteral nutrition group) with 34 groups according to the nutrition support approach.The incidence of nosocomial infections, cellular immunity indexes (CD₃⁺, CD₄⁺, CD₃⁺CD₄⁺ and NK), humoral immunity indexes (IgA, IgM and IgG) and erythrocyte immune indexes (FEER, ATER, DTER and RBC-C3bR) were observed and compared between the two groups of patients. RESULTS The infection rate of the observation group was 2.94%, significantly lower than 17.65% of the control group(P＜0.05).There were no significant differences in the cellular immunity indexes, humoral immunity indexes or erythrocyte immune indexes between the two groups of patients before the treatment; the levels of the cellular immunity indexes CD₃⁺, CD₄⁺, CD₃⁺CD₄⁺ and NK of the observation group were respectively (63.23±5.08)%, (45.30±4.24)%, (32.25±3.41)% and (16.49±1.75)% after the nutrition support therapy for 7 days and were respectively (67.63±5.23)%, (49.24±4.56)%, (35.25±3.66)% and (18.98±2.01)% after nutrition support therapy for 14 days; the levels of the humoral immunity indexes IgA, IgM and IgG of the observation group were respectively (3.03±0.27)g/L, (2.20±0.20)g/L and (12.26±1.50)g/L after the nutrition support therapy for 7 days and were respectively (3.24±0.31)g/L, (2.53±0.24)g/L and (14.17±1.59)g/L after the nutrition support therapy for 14 days; the levels of the erythrocyte immune indexes FEER, ATER, DTER and RBC-C3bR of the observation group were respectively (53.20±5.10)%, (56.20±4.98)%, (32.98±3.10)% and(18.98±2.07)% after the nutrition therapy for 7 days and were respectively (56.56±5.32)%, (59.73±5.10)%, (36.56±3.34)% and (21.24±2.25)% after the nutrition support therapy for 14 days, significantly higher than that of the control group(P＜0.05). CONCLUSION The enteral nutrition support therapy may facilliate the control of the infections in the ICU patients of surgery department and improve the immune function indexes of the patients, and it has great application significance.