OBJECTIVE： To observe clinical efficacy and safety of nitric oxide （NO） combined with sildenafil in the treatment of neonatal pulmonary hypertension. METHODS： 66 cases of neonatal pulmonary hypertension were selected and randomly divided into observation group and control group， with 33 cases in each group. 2 groups of patients were given Dopamine injection 5 μg/（kg·min）， ivgtt. Control group was given NO 5-20 ppm；observation group received oral or nasal feeding of Citric acid sildenafil tablets， 0.5-1.0 mg/kg，96 h， on the basis of control group. Both group received 3 d of treatment. Clinical efficacy of 2 groups were observed as well as the level of PaO2， PaCO2， SaO2， PAP， NO， ET-1， HIF-1α， EPO and Ca2+ before and after treatment. The incidence of ADR was compared between 2 groups. RESULTS： Total effective rate of observation group was 96.97％， which was significantly higher than that of control group （75.76％）， with statistical significance （P＜0.05）. There was no statistical significance in the levels of PaO2， PaCO2， SaO2， PAP， NO， ET-1， HIF-1α， EPO and Ca2+ between 2 groups before treatment （P＞0.05）； compared to before treatment， PaO2， SaO2， No and Ca2+ levels of 2 groups increased significantly after treatment， while PaCO2， PAP， EPO， HIF-1， ET-1 significantly lowered and the observation group was better than the control group， with statistical significance （P＜0.05）. No obvious ADR was found in 2 groups. CONCLUSIONS： Sildenafil combined with NO is effective in the treatment of neonatal pulmonary hypertension and can effectively improve pulmonary hypertension and blood gas indexes with good safety.