Abstract: Objective: To explore the mutual relations among blood sugar,blood sodium,C reactive protein(CRP),multiple organ dysfunction syndrom(MODS) and prognosis of illness when infants with severe pneumonia were complicated by systemic inflammatory response syndrom(SIRS).Methods: Fifty-one cases with severe pneumonia when complicated by SIRS were analyzed including organ failure and the changes of blood sugar,blood sodium,CRP and their relationship,similarly the prognosis of these infants was analyzed.Results: In 51 cases with severe pneumonia,33 cases were complicated by SIRS.Comparing the morbidity rate of MODS and the fatality rate of SIRS infants with non SIRS ones,there were no obvious differences(P>0.05).The blood sugar and CRP levels of SIRS infants were significantly higher than non SIRS group(P<0.01),but the blood sodium level was significantly lower than in non SIRS group(P<0.01).Conclusions: To apply the diagnostic standards of SIRS and the detection of blood sugar,blood sodium and CRP would help to judge the severity of infants with pneumonia,which could instruct paediatric clinical work.Enough attention should be payed to children with SIRS and dynamic examination of blood sugar,blood sodium and CRP.