Objectives: To reveal the characteristics of tricuspid valve in hypoplastic right ventricular heart syndrome (HPRVHS) using 3-D echocardiography. Methods: Twenty eight patients with hypoplastic right ventricle were included in the study. These patients were divided into two groups according to the degree of tricuspid regurgitation. Eighteen normal children were included as control. The Volume of right ventricle (Vrv),the area of tricuspid annulus (A TVA) and leaflets,the distance from tips of leaflets to the nearest papillary muscles were measured in three dimensional echocardiogram using Q-lab image processing software. These data were standardized by body surface area (BSA). Results: The A-TV was significantly correlated with the volume of right ventricle (r=0.90, P<0.0001). In the tricuspid regurgitation group, the ratio of the area of anterior leaflet (A an) to the area of tricuspid annulus (A TVA) was significantly higher than that in non-regurgitation group and normal group (ratio=0.55±0.044,P<0.0001). The ratio of the Area of the posterior leaflet (A po) to the area of tricuspid annulus (A TVA) in regurgitation group was significantly less than that in normal and non-regurgitation groups. The distance from tips of leaflets was significantly shorter in HPRVHS than in normal group.Distance from the tip of septal leaflet to the nearest papillary muscle is shorter in regurgitation group than in non-regurgitation group (p=0.0023). Conclusions: 3-dimensional echocardiography could be applied for evaluating the pathologic changes of tricuspid valve . In HPRVHS, hypoplasty of posterior leaflet and shortness of the cords of septal leaflet could be the causes of tricuspid regurgitation.