Abstract: Objective: To explore the application value of end-tidal carbon dioxide partial pressure(P_ETCO₂) monitoring in mechanical ventilation of neonatal respiratory distress syndrome(NRDS).Methods: The P_ETCO₂ and 122 arterial blood gas of 30 cases with NRDS treated with mechanical ventilation were monitored.The relation of P_ETCO₂ and arterial carbon dioxide partial pressure(PaCO₂) were analyzed.Results: The average value of P_ETCO₂ and PaCO₂ were(31.7±5.3) mmHg and(37.6±4.5) mmHg,respectively,which was a positive correlation(P<0.05).With the increasing of oxygenation index(OI) value,the r values of P_ETCO₂ and PaCO₂ were decreased.When the OI value was more than 25,there was no correlation between PaCO₂ and P_ETCO₂.PaCO₂ and P_ETCO₂ was positive correlation after mechanical ventilation,the difference of which were decreased.Twenty-seven cases survived,and three cases died.Conclusions: When the OI value is less than 25 or children with NRDS get better,the P_ETCO₂ and PaCO₂ has a good correlation during the period of mechanical ventilation.