Abstract：Objective To explore the value of lung ultrasound score （LUS） in guiding the early application of pulmonary surfactant （PS） to premature infants with respiratory distress syndrome （RDS）. Methods Prospectively selected 184 premature infants with RDS admitted to the neonatal intensive care unit （NICU） of our hospital from March 2017 to April 2019. According to the random number table method, they were divided into ultrasound guidance group and control group, with 92 cases in each group. All premature infant were transferred to the NICU for continuous positive airway pressure （CPAP） after birth. The ultrasound-guided group underwent pulmonary ultrasound examination within 3 hours after birth. When the LUS score was ＞4 or FiO2＞0.4, PS was given. In the control group, PS treatment was given only when FiO2＞0.4; the first dose was 200 mg/kg, and if FiO2＞0.4 after 12 hours, the second dose was 100 mg/kg. Observed the early PS usage rate and the maximum FiO2 value before PS use in the two groups; the continuous positive pressure ventilation time, invasive ventilation time, oxygen therapy time, the number of days without ventilator in 28 days, the incidence of bronchopulmonary dysplasia （BPD） and the 28-day mortality rate were compared and the risk factors affecting the occurrence of BPD were analyzed.  Results （1） The use rate of PS in the ultrasound-guided group was higher than that in the control group within 3 hours after birth, the difference between two groups was statistically significant （χ2＝9.069，P＜0.05）; the FiO2 level in the ultrasound-guided group was lower than that in the control group when the first dose of PS was used, the difference between two groups was statistically significant （t＝11.213, P＜0.05）. （2） Invasive ventilation time and oxygen therapy time in the ultrasound guidance group were lower than those in the control group, the differences between two groups were statistically significant （t＝11.359, 7.986, 7.928，all P＜0.05）; the time of CPAP between group were compared and the difference was no statistically significant （t＝0.622, P＞0.05）. （3） The incidence of BPD in the ultrasound-guided group was lower than that in the control group, and the difference was statistically significant （χ2＝4.754, P＜0.05）; there was no statistically significant difference in 28 d mortality between the two groups （χ2＝0.505，P＞0.05）. （4） Multivariate logistic regression analysis showed that birth weight ＜1 500g （OR＝1.013） and mechanical ventilation time （OR＝1.140） were the risk factors for the occurrence of BPD, early lung ultrasound evaluation （OR＝0.121） was the protective factors for the occurrence of BPD （P＜0.05）. Conclusion The use of LUS to guide the early application of PS in premature infant with RDS can improve the use rate of PS, reduce the time of mechanical ventilation and oxygen therapy, and reduce the incidence of BPD, which is worthy of clinical reference.