Objective To evaluate the efficacy of pulmonary surfactant (PS) on severe acute respiratory distress syndrome (ARDS) in different age baby with congenital heart disease. Methods We divided 43 baby patients into two separate groups including a little baby group (12 patients with age less than 3 months) and an infants group (31 patients with age of 3 months to one year). Both groups of patients were treated with intratracheal PS at the same time. The clinical data were collected and analyzed. Results The little baby group had lower body weight. There was no statistical difference in the cardiopulmonary bypass (CPB) time, operation blocking time, mechanical ventilation time, ICU stay time between the two groups (P>0.05). Before treatment, arterial partial presurre of oxygen (PaO2), fractional oxygen concentration in inspire gas (FiO2), the ratio of arterial PO2 to the inspired oxygen fraction (P/F) and arterial-alveolar N2 difference or gradient (a/A) had no difference between the two groups (P>0.05). After treatment, PaO2 and P/F of both groups were significantly lower than before (P<0.05), and FiO2 and P/F were significantly higher than before (P<0.05). After 24 h of treatment, PaO2 and P/F of the little baby group was significantly higher than that of the infants group (P<0.05), and FiO2 and P/F were significantly lower than those of the infants group (P<0.05). Conclusion PS treating severe ARDS in little baby with congenital heart disease has better effect than infants.