【Abstract】 Objective To improve the knowledge of idiopathic pulmonary arterial hypertension ( IPAH) to elevate the levels of early diagnosis and treatment. Methods The clinical data of 39 IPAH patients admitted in Beijing Anzhen Hospital from October 1997 to June 2010 were reviewed. Results Of the 39 IPAH patients, 14 cases were male and 25 cases were female, with an average age of ( 29. 7 ±16. 4)years old. Main clinical manifestations were exertional dyspnea/breathlessness ( 90. 9% ) , chest tightness( 72. 7%) , chest pain ( 30. 7% ) , cough ( 41. 0% ) , fatigue ( 48. 7% ) , syncope ( 35. 9% ) , cyanosis( 28. 2% ) , edema of lower extremity ( 43. 6%) , etc. As revealed through echocardiography, 39 cases had a mean systolic pulmonary arterial pressure ( SPAP) of ( 88. 8 ±24. 2) mmHg, with right ventricle enlargementin 37 cases and normal in 2 cases. Pulmonary angiography showed central pulmonary arterial dilatation with pruning of the peripheral blood vessels in 36 cases and normal in 3 cases. Right heart catheterization and acute vasodilator testing was performed with iloprost in 15 patients, systolic pulmonary arterial pressure was( 77. 6 ±27. 8 ) mm Hg, and positive rate was 20. 0% . 24 cases were misdiagnosed at admission, and misdiagnosis rate was 61. 5% . The average time of misdiagnosis was ( 26. 0 ±24. 5) months. 20 cases were treated with general medical therapy and 1 case was managed with lung transplantation before April 2008.Then 13 cases were given pulmonary arterial hypertension-targeted therapies, including sidenafil, iloprost or bosentan. Two patients died in hospital with a mortality rate of 5. 1% . Conclusions IPAH is uncommon and often occurs in young and middle-aged women. The symptoms are nonspecific and easily misdiagnosed.Echocardiography and pulmonary angiography are helpful in diagnosis. Right heart catheterization and acute vasodilator testing should be carried out if available. The patients should be early treated with pulmonary arterial hypertension-targeted therapies. Lung transplantation may be an option for end-stage cases.