To analyze the clinical efficacy of nutrition support therapy combined with antibiotics in the treatment of patients with ICU severe community-acquired pneumonia and its effect on serum procalcitonin (PCT) and C reactive protein (CRP). A total of 90 patients with ICU severe community-acquired pneumonia treated in hospital from September 2016 to June 2017.The patients were randomly divided into A group and B group 45 cases in each group. Both groups were given antibiotic treatment of azithromycin plus cefuroxime sodium in which the A group received enteral nutrition support therapy while the B group parenteral nutritional support therapy. Levels of serum prealbumin (PA), albumin (ALB), transferrin (TF), procalcitonin (PCT) and C reactive protein (CRP) before and after treatment were compared. Before treatment there was found no significant difference in serum PA, ALB and TF levels (p>0.05) while after treatment, the serum levels of PA, ALB and TF in the A group were significantly higher than those in the B group (p<0.05). The effective rate of the A group was 88.9%, higher than that of the B group (p<0.05). In patients with ICU severe community-acquired pneumonia, the treatment of enteral nutrition support therapy combined with antibacterial drugs of azithromycin and cefuroxime sodium can effectively improve the indexes of PA, ALB and TF. The reduce levels of serum PCT and CRP with the good prognosis is important in popularization and application in clinical practices.