objective: to investigate the correlation of pulmonary artery pressure assessment at different phases by CW Doppler Echocardiography and cardiac catheterization in patients with Idiopathic Pulmonary Arterial Hypertension (IPAH) . Methods: 113 cases of patients with symptoms of chest stuffy and pneumatic, etc. are suspicious of IPAH in our hospital from June 2013 to March 2016 were enrolled in the study, in the 78 patients diagnosed with cardiac catheterization, Main pulmonary artery diameter (MPA), right atrium transverse diameter (RAT), end-diastolic transverse diameter ( LVT) and axial diameter of both right and left ventricle (RVD, LVD) were measured by echocardiogram, the ratio of transverse diameter between right ventricle and left ventricle (RVT/LVT), the ratio of axial diameter (RVD/LVD). Peak systolic pressure of pulmonary artery was evaluated by pressure gradient of tricuspid regurgitation with Doppler echocardiogram。The peak diastolic pressure and average pressure of pulmonary artery was assessed with the earlier and late pressure gradient via pulmonary regurgitation. These pressure measurements at different phases with both the Doppler assessment via tricuspid and pulmonary valve regurgitation and cardiac catheterization were compared, and the correlation was analyzed as well. Results:1.Sensitivity,specificity,positive predictive value，negative predictive values and accuracy of CW Doppler Echocardiography Was 87.2%,74.3%,88.3%,72.2%，83.2%. 2.There were 74 cases with tricuspid regurgitation, 62 cases with pulmonary valve regurgitation and 58 cases with both situations in all the 78 patients. There were good correlation on PASPe, PADPe and PAMPe between the values with Doppler echocardiogram and cardiac catheterization method (r=0.667,0.639,0.636，all P<0.05). There were good correlation between the echocardiographic parameters of MPA, RAT, RVT/LVT, RVD/LVD and PASPc (P<0.05), significant correlation was noted between RAT、RVT/LVT,RVD/LVD and PASPc(P<0.001). Conclusion: There were significant correlations on the pulmonary artery pressure at different phases measured by tricuspid regurgitation and pulmonary valve regurgitation between Doppler echocardiography and cardiac catheterization in patients with IPAH. It is the first method on the noninvasive assessment of pulmonary hypertension in patients with IPAH.