Abstract: Objective：To study the effects of different nutritional support schemes on intestinal flora， nutritional indicators and long-term prognosis in severe community acquired pneumonia (CAP) patients. Methods：62 patients with severe CAP who received treatment in our hospital were selected from January 2016 to December 2017. They were divided into the control group and the observation group using random number table，each group had 31 cases. The control group was given routine enteral nutrition support， and the observation group was given enteral immune microecological nutrition support. Compared the inflammatory factors， intestinal flora，nutritional indicators and prognosis between the two groups. Results： The nutritional indicators of the two groups were similar before treatment (P>0.05). The level of TRF and PAB in the two groups increased after treatment， and the level of PAB and TRF in the observation group was higher than those of the control group (P<0.05). After treatment， the levels of IL-6， hs-CRP and TNF-α in the two groups were decreased，while the levels of IL-6， hs-CRP and TNF-α in the observation group were lower than those of the control group (P<0.05). 10 d after the onset， the bacterial flora imbalance rate was 3.23% (1/31) in the observation group and 19.35% (6/31) in the control group.The difference was statistically significant (χ2=4.026， P=0.045). The time of mechanical ventilation and ICU stay in the observation group were shorter than those of the control group (P<0.05). The time of antibiotic use and the incidence of complications in the two groups were similar (P>0.05). Conclusion：Early enteral nutrition support can obviously improve the prognosis of severe CAP patients and reduce the level of inflammatory factors. Enteral immune microecological nutrition support can better improve the nutritional status of severe CAP patients，reduce the level of inflammatory factors，improve the intestinal microecological environment and improve the prognosis of patients.