Abstract: Objective To evaluate the clinical value of pulmonary ultrasound score in evaluating the severity of neonatal infectious pneumonia(IPN). Methods From July 2017 to July 2019, 150 cases of children with IPN confirmed in our hospital neonatal intensive care unit were selected. According to the presence of respiratory failure, they were divided into no respiratory failure group(62 cases) and respiratory failure group(88 cases). According to neonatal critical illness score(NCIS), children with respiratory failure group were divided into critical group(26 cases), critical group(33 cases) and extremely critical group(29 cases). Pulmonary ultrasound examination and pulmonary ultrasound score were performed on the children, and the pulmonary ultrasound score, oxygenation index(OI), respiratory index(RI) and NCIS indexes were compared among and within the groups, and the correlation between pulmonary ultrasound score and NCIS score, OI and RI was analyzed. Results The pulmonary ultrasound score and OI indexes in the respiratory failure group were significantly lower than those in the non-respiratory failure group(all P<0.01), and the RI indexes were significantly higher than those in the non-respiratory failure group(P<0.01). In the respiratory failure group, the pulmonary ultrasound score, NCIS score and OI index decreased significantly and RI index increased significantly with the aggravation of the disease(all P<0.01). According to ROC curve analysis, the optimal prediction value of pulmonary ultrasound score in IPN children with respiratory failure was 31 points, the sensitivity and specificity were 85.8% and 76.9%, respectively. The optimal prediction value of critical condition was 27 points, the sensitivity and specificity were 86.3% and 85.7%, respectively. The optimal prediction value of extremely critical condition was 17 points, the sensitivity and specificity were 76.9% and 91.8%, respectively. Pearson analysis showed that the pulmonary ultrasound score of children with respiratory failure was positively correlated with NCIS score and OI index(all P<0.05), and negatively correlated with RI(P<0.05). Conclusion Pulmonary ultrasound score can effectively assess the severity of newborn IPN, and provide a reference for clinicians to understand the severity of the disease and reasonable treatment of the children, which has high clinical application value.