To establish a stable and reliable non−invasive method for evaluating the right heart structure and function in rats with pulmonary hypertension (PH) using small animal echocardiography. Male SD rats were randomly divided into a control group and a model group. The model group was injected subcutaneously with the vascular endothelial growth factor receptor inhibitor SU5416 (20 mg/kg body weight) in the neck and placed in a hypoxia chamber with 10% oxygen concentration for 3 weeks, then transferred to a normoxia environment for another 3 weeks to construct a severe PH rat model. The control group was raised in a normal environment. Six weeks after modeling, animals were anesthetized, and echocardiographic measurements and right heart catheterization were performed to collect relevant hemodynamic indices. Echocardiographic indices of the rat hearts were analyzed for uniformity and retest reliability, correlated with the right ventricular systolic pressure measured by right heart catheterization, and their diagnostic value for PH rats was evaluated. The right heart structure and function evaluation indices established in PH rats using small animal echocardiography showed good uniformity and retest reliability. The end−diastolic right ventricular free wall thickness, end−systolic right ventricular free wall thickness, tricuspid annular plane systolic excursion, and pulmonary artery flow acceleration time/ejection time and pulmonary artery flow acceleration time were significantly correlated with the right ventricular systolic pressure measured by right heart catheterization (P<0.001) and had high diagnostic value. Small animal echocardiography provides a non−invasive, stable, and reproducible method for evaluating the right heart structure and function in PH rats, which can be used to assess the severity of the disease in PH rat models.