Objective: To explore the application of lung ultrasound score by echocardiography in evaluating extravascular lung water before and after operation in children with congenital heart disease. Method: 88 cases of children with congenital heart disease were analyzed before and post operative with echocardiography. Lung water were observed through different windows. Lung ultrasound scores derived from chidren before surgery was compared with those from postoperative, and the relationship between lung ultrasound scores and Qp /Qs was analyzed. Results Lung ultrasound scores of the children with ventricular septal defect (VSD), atrial septal defect (ASD) and total anomalous pulmonary venous drainage (TAPVD) were higher before surgery than postoperative (P <0.01), but there was no significant difference (P﹥0.05) between them in Tetralogy of Fallot (TOF) group. Lung ultrasound scores of children with VSD and TAPVD before surgery positively correlated with Qp/Qs (P<0.01). Conclusion: Lung ultrasound scores derived from echocardiography can reflect the changes of extravascular lung water of children with congenital heart disease during perioperative, and be used to assess the heart and lung function of the patients, screen critically ill children, guidline clinical early intervention.