Objective To explore the value of lung ultrasound score(LUS)and diaphragm ultrasound combined with routine indicators in predicting the occurrence of acute respiratory distress syndrome(ARDS)in children with severe pneumonia(SP).Methods A total of 160 patients with SP were selected from Kunming Children's Hospital from August 2022 to August 2023,all of whom underwent lung ultrasound and diaphragm ultrasound examination to obtain LUS and diaphragm ultrasound parameters[diaphragm mobility(DM),diaphragm thickness change rate(TF)].The patients with SP were divided into ARDS group and non-ARDS group according to whether they were complicated with ARDS during hospitalization.The general data,serum inflammatory factor levels,LUS and diaphragm ultrasound parameters were compared between the two groups at admission,and the influencing factors of ARDS in children with SP were analyzed,and the value of LUS and diaphragm ultrasound parameters in predicting ARDS in children with SP was analyzed.Results The incidence of ARDS in SP patients was 41.88％(67/160).APS,APACHE Ⅱ scores,serum C-reactive protein(CRP),interleukin-6(IL-6),high mobility group protein B1(HMGB1)levels,LUS and DM in ARDS group were higher than those in non-ARDS group,TF were lower than those in non-ARDS group(P＜0.05).APS,APACHE Ⅱ scores,serum CRP,IL-6,HMGB1 levels,LUS,DM,TF were the influencing factors of ARDS in SP children at admission(P＜0.05).The area under the curve(AUC)of LUS,DM and TF predicted ARDS were 0.718,0.742 and 0.720,respectively.The AUC of the conventional prediction scheme(APS,APACHE Ⅱ score combined with serum CRP,IL-6 and HMGB1 levels at admission)was 0.852,while that of the new prediction scheme(combined with LUS,DM and TF based on the conventional prediction scheme)was 0.930.The AUC of the new prediction scheme was significantly higher than that of the conventional prediction scheme(P＜0.05).Conclusion LUS,DM,TF,and SP parameters of the diaphragm are significantly correlated with ARDS in children with SP,and the combination of routine indicators can provide reliable evidence for clinical prediction of ARDS in children with SP.