Objective To explore the clinical characteristics,laboratory examination indicators,and auxilia-ry examination results of critically ill children with adenovirus pneumonia,screen relevant indicators with warning effects for critically ill children with adenovirus pneumonia,and construct an early identification scale for critically ill children with adenovirus pneumonia.Methods The clinical data of totally 86 children with adenovirus pneumonia admitted in the hospital from May 2021 to September 2023 were retrospectively ana-lyzed,and multivariate Logistic regression analysis was used to screen relevant indicators for the early identifi-cation of severe adenovirus pneumonia in children.The sensitivity and the specificity were analyzed using the receiver operating characteristic(ROC)curve.Experts conducted a quantitative evaluation of the weight scores of each factor,and finally an early identification scale for critically ill children with adenovirus pneumo-nia was developed.Results Among 86 children with severe adenovirus pneumonia,34 were critically ill with adenovirus pneumonia.There were statistically significant differences in the incidence of respiratory distress,respiratory distress,consciousness and behavior disorders,respiratory symptoms,cardiovascular symptoms,and neurological symptoms between the two groups(P<0.05).The differences of white blood cell count,platelet count,erythrocyte dynamic sedimentation rate,serum ferritin,serum ferritin/erythrocyte dynamic sed-imentation rate,R-glutamyltransferase,alanine aminotransferase,lactate dehydrogenase between the severe group and the critically ill group were statistically significant(P<0.05).Multivariate Logistic regression a-nalysis showed that white blood cell count,platelet count,alanine aminotransferase,serum ferritin/erythrocyte dynamic sedimentation rate and lactate dehydrogenase were all influencing factors for the progression to criti-cal illness in children with adenovirus pneumonia(P<0.05),and the ROC curve results showed that the area under the curve of the diagnostic model composed of white blood cell count,platelet count,alanine aminotrans-ferase,serum ferritin/red blood cell dynamic sedimentation rate,and lactate dehydrogenase for diagnosing crit-ical illness was 0.864,and the sensitivity and the specificity were 86.42%and 82.76%,respectively.After 25 peer experts evaluated the weight scores of various clinical manifestations and examination items,the early i-dentification scale for critically ill children with adenovirus pneumonia was finally developed.Conclusion Dur-ing clinical treatment,the clinical manifestations of children with adenovirus pneumonia can be considered in conjunction with relevant auxiliary examination results,and early identification scales can be used to determine whether children with adenovirus pneumonia are at risk of developing into critical illness.