Objective To investigate the effects of immune—enhancing enteral nutritioin therapy on the inflammatory reaction and immune function in the rats of ventilation-induced lung injury．Methods Fourty rats were divided into four groups(EN1、EN2、SEN1、SEN2，n=10)．All groups were performed mechanic ventilation and fed isocaloric enteral nutrition．EN1 group：tidal Volume(VT) =8 mL／kg，traditional enteral nutrition；EN2 group：VT=40 mL／kg，traditional enteral nutrition；SEN1 group：VT：8 mL／kg，immune-enhancing enteral immunonutrition；SEN2 group：VT=40 mL／kg，immune-enhancing enteral immunonutrition．Lymphocyte subsets，TNF-α，IL-6 and contents of arachidonic acid(AA)were determined at different time point(0，4，24，72 h after ventilation)．Results The levels of CD3+，CD4+，CD4+／CD8+ in SEN2 group were lower(Plt;0.05)than in EN1，EN2 and SEN1 group after 24，72 h of ventilation．The serum concentrations of TNF-α，IL-6 and AA were significantly lower in EN2 than in other three groups(P lt;0.05)．Conclusion Immune-enhancing enteral nutrition feeding prior to machanie ventilatioin can alleriate the damage of immunological function and reduce infl ammotory responses