Background Real-time three-dimensional volume echocardiography could obtain ventricular volume and ejection fraction rapidly and non-invasively without relying on ventricular morphology. Infants under one year of age with medium to large ventricular septal defect(VSD) and pulmonary hypertension have the characteristics of recurrent pulmonary infection and feeding difficulties. For these children, early surgery is recommended to reduce pulmonary congestion. Evaluation of biventricular volume and pumping function is important to determine the time of surgery.Methods In this study 18 children with medium to large VSD complicated with pulmonary hypertension (VSD/PH group ) and 18 healthy children of the same age (control group) were recruited. Biventricular diameter, volume and systolic function were evaluated by two-dimensional echocardiography (2DE), M-mode, tissue Doppler and real-time three-dimensional echocardiography (RT-3DE). The measurements included: left and right ventricular diameter, body surface area standardized ventricular volume (LVEDV/BSA, RVEDV/BSA), LVEF ( M-mode), TAPSE (tricuspid annulus displacement), TAV (tricuspid annulus velocity), LVEF (RT-3DE), RVEF (RT-3DE). Results Both left and right ventricular diameter and LVEDV/BSA, RVEDV/BSA were significantly larger than those in normal controls (P <0.05). Compared with normal group, LVEF (RT-3DE), RVEF (RT-3DE) and TAV in VSD/PH group decreased (P <0.05). However there were no significant difference in LVEF (M-mode) and TAPSE between the two groups (P >0.05).Conclusion RT-3DE provides a new approach for noninvasive and rapid assessment of cardiac volume and systolic function for infants with ventricular septal defect and pulmonary hypertension.