The objective of this study was to assess the effects of intravenous iIoprost in the treatment of pulmonary hypertension in the patients after open-heart surgery at National Hospital of Pediatrics. The results showed that systolic pulmonary artery pressure decreased after iIoprost treatment: from 47.22 + or - 9.76mmHg to 40.38 + or - 9.61 mmHg (p 0.001) after 4 hours of time and 35.25 + or - 10.14mmHg (p 0.001) after 24 hours, which had statistical significance. Blood pressure was stable before and after iIoprost therapy. The patient respiratory improved with FiO2 gradually decreasing from 83 + or - 22.1 percent to 52.97 + or - 21.83 percent with P 0.001, PaO2/FiO2 increased from 189.65 + or - 114.05 to 286.54 + or - 199.92 with P 0.001. Diuresis increased from 2.36 + or - 1.07 ml/kg/h to 3.36 + or - 1.3 ml/kg/h and blood lactate decreased from 1,52 + or - 0.76 to 1.00 + or - 0.53 (p 0.001). In conclusion, Intravenous iIoprost combined with routine measures effectively in the treatment of perioperative pulmonary hypertension.