Objective To establish reference ranges for right ventricular functional parameters at defined postnatal time points in neonates, thereby providing a basis for precise hemodynamic assessment and clinical management of critically ill neonates. Methods In a prospective multicenter observational study, clinical and echocardiographic data were collected from 406 term neonates who were admitted to neonatal departments or seen in outpatient clinics of three centers (Children's Hospital of Chongqing Medical University, Yinchuan First People's Hospital, and Inner Mongolia Maternal and Child Health Care Hospital) between June 2023 and May 2024. Bedside echocardiography was used to measure right ventricular functional parameters. Spearman rank correlation was applied to assess associations between each parameter and sex, birth weight, gestational age, and postnatal age. Reference ranges were constructed using the 95% confidence interval approach for postnatal days 1, 3, 7, 14, and 28, with stratification by gestational age and birth weight. Results Among the right ventricular functional parameters, right ventricular fractional area change (RV-FAC), tricuspid annular plane systolic excursion (TAPSE), and tricuspid annular peak systolic velocity were positively correlated with gestational age and birth weight (all P<0.05). RV-FAC, TAPSE, right ventricular outflow tract velocity-time integral, tricuspid annular peak systolic velocity, tricuspid inflow E-wave peak velocity, tricuspid inflow E/A ratio, and peak early diastolic velocity of the lateral tricuspid annulus (e') were positively correlated with postnatal age (all P<0.05). None of the right ventricular parameters was correlated with sex (all P>0.05). Reference ranges for postnatal days 1, 3, 7, 14, and 28 were established with stratification by gestational age and birth weight. Conclusions Multiple parameters of neonatal right ventricular systolic and diastolic function are associated with postnatal age, gestational age, and birth weight. The comprehensive, stratified reference ranges for right ventricular functional parameters established in this study may serve as an important reference for refined hemodynamic assessment and management in critically ill neonates.