Abstract： Objective:To analyze the predictive value of Body Mass Index (BMI), serum albumin (ALB) combined with Modified Nutrition Risk in Critically Ⅲ (mNUTRIC) score for the prognosis of patients with severe pneumonia.Methods:232 patients with severe pneumonia hospitalized in the intensive care unit (ICU) of Fangcun branch of Guangdong Provincial Hospital of traditional Chinese medicine from January 2017 to August 2020 were retrospectively collected. The patients were divided into observation group (182 case) and control group (50 case) according to the outcome of ICU hospitalization. General Information, BMI, serum ALB, laboratory examination, length of stay, length of mechanical ventilation, acute physiology and chronic health evaluation Ⅱ (APECHE Ⅱ), sepsis-related organ failure assessment (SOFA), pneumonia severity index (PSI) score and mNUTRIC score were compared between 2 groups. Logistic regression was used to analyze the risk factors of death of severe pneumonia. Receiver operating characteristic (ROC) curve was used to analyze the predictive value of the factors affecting the prognosis of severe pneumonia.Results:Age of the observation group (80.0 vs. 76.5), arterial blood lactic acid(1.90 vs.1.65 mmol/L), duration of mechanical ventilation (242.0 vs. 165.5)h, SOFA score (6 vs. 5) and mNUTRIC score (5 vs. 4) were higher than control group (P<0.05); BMI of the observation group (20.10 vs. 21.50 kg/m2), ALB[(32.34±5.98) vs.(35.12±6.09)g/L] was lower than control group (P<0.05). Age, and SOFA score are risk factors for death from severe pneumonia; low serum ALB, Low BMI, mNUTRIC score were independent risk factors for death from severe pneumonia; The AUCs for age, BMI, ALB, mNUTRIC scores and SOFA scores to assess the prognosis of patients with severe pneumonia were 0.618, 0.651, 0.653, 0.660, 0.600(P<0.05). The AUC for BMI combined with ALB was 0.682; The AUC for the combination of age, BMI and ALB was 0.709; The AUC for the combination of BMI, ALB and SOFA score was 0.715; The AUC for the combination of age, BMI, ALB and SOFA score was 0.732; The AUC for the combination of BMI, ALB and mNUTRIC score was 0.735(P<0.05).Conclusion:BMI, ALB, and mNUTRIC scores are valuable in assessing the prognosis of patients with severe pneumonia, and the combined of them can further improve the predictive value of short-term prognosis of patients with severe pneumonia.