Background: Use of lung ultrasonography (LUS) to diagnose neonatal pneumothorax (PTX) has been well documented. This study aimed to emphasize the value of precordial heart image (PHI) disappearance as an ultrasound sign to diagnose neonatal PTX and to perform thoracentesis at the precardiac area in patients with PTX.Methods: From March 2017 to May 2021,a total of 288 infants were included in this retrospective study, including 48 patients with PTX,48 patients with respiratory distress syndrome,48 patients with transient tachypnea,48 patients with meconium aspiration syndrome,48 patients with pneumonia,and 48 patients with normal lung tissue.LUS was performed routinely,and thoracentesis was performed under LUS guidance.Results: Eight of 48 patients with PTX (16.7%) presented with PHI disappearance on LUS,which exhibited a sensitivity of 16.7% and a specificity of 100% for diagnosing neonatal PTX.Needle aspiration was performed on 42 patients with PTX (87.5%),8 of whom underwent puncture at the precardiac area. Satisfying results were obtained in 40 patients (95.2%) without any complications.Conclusion: PHI disappearance is an uncommon ultrasound sign on LUS that can be used to diagnose neonatal PTX.Selection of the precardiac area as the puncture site is safe for the treatment of neonatal PTX in patients with PHI disappearance.