Pulmonary atelectasis (PA) is a common clinical complication among newborns, and it is one of the most common causes of neonatal dyspnea, a condition with no specific effective treatment. This study examined the effectiveness and security of bronchoalveolar lavage (BL) regarding the treatment of neonatal PA under ultrasound monitoring.A total of 57 patients diagnosed with PA via lung ultrasound (LUS) were included in this study. All patients received BL via a tracheal intubation injection of lavage fluid. The LUS was conducted immediately after each lavage to understand the conditions of lung re-expansion. Irrigation was repeated two to three times as one course of treatment. BL was provided as one to two courses of treatment daily for several days according to atelectasis and lung recruitment status.Of the 57 patients, BL was very effective in 44 cases (77.2%), marginally effective in nine cases (15.8%) and ineffective in four cases (7.0%), showing a total effective rate of 93.0%. The four ineffective cases showed a long disease duration and severe pulmonary consolidation.BL showed significant effectiveness for the treatment of neonatal PA under ultrasound monitoring. This treatment is easy to operate, and no adverse side effects were observed. Thus, BL should be considered for clinical application.