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 in-to 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 tab-lets,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 inci-dence of ADR was compared between 2 groups. RESULTS:Total effective rate of observation group was 96.97%,which was sig-nificantly 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);com-pared 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.