Objective The pulmonary artery (PA) in patients with pulmonary hypertension (PH) was investigated by combination of ultrasound with biomechanical method. The present article is to apply mechanical parameters of PA on evaluation of properties of PH clinically. Methods Patients with ventricular septal defect with PH were selected and all cases were underwent interventional test of right heart catheterization. PA pressure and dimension of two-dimensional images were recorded, measuring in 10 points within systole. The systolic increment of both pressure and dimension of PA were calculated. The data of PA pressure and dimension were input into constitutive equations for biomechanical measurement to calculate stress-strain relation in PA. Results With increase of pulmonary pressure, the enlargement of PA dimensions was limited, especially in the high pulmonary vascular resistance subgroup of PH. Both of the constants a and b decreased at the same time significantly (P<0.001) in the subgroup, which showed the predictive value for property of PH. Conclusion Ultrasonic and biomechanical method of PA would be useful in predicting property and pathological process of PH, which would provide a new way in selection of surgical treatment for congenital heart disease with PH potentially.