Abstract: Objective：To study the effect of combined treatment of lung surface active substance with mechanical ventilation for neonatal pulmonary hemorrhage.Methods：Totally 102 neonates with neonatal pulmonary hemorrhage were randomly assigned into the control group (51 cases, given endotracheal injection of blood clotting enzyme and epinephrine) and the observation group (51 cases, given endotracheal injection of blood clotting enzyme and lung surface active substance). Pulmonary bleeding areas, pulmonary hemorrhage duration, mechanical ventilation duration, and adverse reactions were observed respectively at 6 hours，12 hours, 24 hours, and 48 hours after treatment.Results：Twelve hours, 24 hours, and 48 hours after treatment, the difference of pulmonary hemorrhage areas in the two groups were statistically significant compared with that before treatment in both groups(P<0.05).The pulmonary hemorrhage areas of the observation group at 12 hours, 24 hours, and 48 hours after treatment were much smaller than the control group, the difference being statistically significant(P<0.05). Pulmonary hemorrhage duration and mechanical ventilation duration were significantly shorter than the control group(P<0.05).The cure rate of the observation group（84.31%,4-3/51） was significantly higher than that of control group（66.67%,34/51）(P<0.05). There were no obvious adverse reactions in the two groups.Conclusion：The combined treatment of mechanical ventilation with lung surface active substances can significantly reduce the lung bleeding areas, shorten the duration of pulmonary hemorrhage and mechanical ventilation, and improve the cure rate.

Key words: Pulmonary hemorrhage, Mechanical ventilation, Lung surface active substance, Baby