Neonatal pneumothorax is a life-threatening condition. Chest X-ray is the main diagnostic method but has some defects. Lung ultrasound has emerged as a diagnostic method in recent years. The aim of this review was to compare the diagnostic accuracy of lung ultrasound against chest X-ray in neonates with pneumothorax. We searched the Chinese journal full-text database, Wanfang database, China biomedical document service system, Weipu Chinese science and technology periodical full-text database, EMBASE, PubMed, The Cochrane Library and Web of Science (up to January 2020) for prospective studies on the diagnostic accuracy of lung ultrasound in neonates with pneumothorax. Statistical analysis was undertaken using Meta-DiSc software, version 1.4 (Romany Cajal Hospital, Madrid, Spain). The search returned 528 studies, of which 8 full texts were assessed for eligibility against the inclusion/exclusion criteria. The overall specificity and sensitivity of lung ultrasound in the diagnosis of neonatal pneumothorax was 98% (95% confidence interval [CI]: 0.94–0.99) and 99% (95% CI: 0.98–1.00), respectively. The diagnostic odds ratio was 920.01 (95% CI: 265.81–3184.33), and the area under the curve was 0.996 7 (Q* = 0.978 5). However, the chest X-ray was always taken as the reference standard with a sensitivity of 82% (95% CI: 0.72–0.90), a specificity of 96% (95% CI: 0.90–0.99) and a diagnostic odds ratio of 44.54 (95% CI: 4.30–460.98). Study analysis studies indicated that the sensitivity of lung ultrasound in diagnosing pneumothorax excepted chest X-ray as the single diagnosis criteria was 98% (95% CI: 0.93–1.00), the specificity was 100% (95% CI: 0.96–1.00) and the diagnostic odds ratio was 965.39 (95% CI: 161.195781.93), showing a higher accuracy than chest X-ray. In conclusion, lung ultrasound had better sensitivity and specificity than chest X-ray in the diagnosis of pneumothorax. Some ultrasonic signs (absence of lung sliding or B-lines) had a high sensitivity in the diagnosis, which could be used to diagnose pneumothorax. Lung point could help judge the severity of pneumothorax. Its presence indicates that pneumothorax is mild to moderate; otherwise, pneumothorax is severe.