Objective To investigate the clinical effect of Ulinastatin intravenous drip in the treatment of severe pneumonia in children.Methods60 children with severe pneumonia treated in our hospital from February 2013 to December 2016 were selected as subjects and divided into control group and study group according to random number method,each group had 30 cases.The patients in the control group received routine treatment,and the patients in the study group were treated with Ulinastatin.The body temperature returned to normal time,white blood cell(WBC)count recovery time,hospitalization time,acute physiology and chronic health evaluation (APACHE-II)and related indexes of lung function and inflammatory stress related indexes of patients in the two groups were compared.Results The body temperature returned to normal time,the WBC count returned to normal time and hospitalization time of patients in the study group were significantly shorter than those in the control group,and the differences were statistically significant(P＜0.05).The score of APACHE-Ⅱof patients in the study group was lower than that of control group,and the difference was statistically significant(P＜0.05).After intervention,the PO2,PaO2/FiO2and lung adaptability of the study group were higher than those in the control group,and P(A-a)O2and respiration rate were lower than those in the control group,and the differences were statistically significant(P＜0.05).After intervention,two groups of patients of IL-1β,TNF-α,CRP,IL-8,PCT levels were significantly lower than before intervention,and the above indices of patients in the study group were significantly lower than the control group,the differences were statistically significant(P＜0.05).Conclusion Ulinastatin intravenous drip can significantly alleviate inflammatory reaction and improve lung function in the treatment of severe pneumonia in children,and has definite clinical efficacy.