Abstract: Objective To investigate the effects of early continuous positive airway pressure(CPAP)on blood gas indexes and prognosis of children with severe pneumonia and respiratory failure. Methods A total of 68 children with severe pneumonia and respiratory failure admitted to our hospital were selected as research subjects. According to the random odd and even number method, all children were divided into control group and study group, with 34 cases per group. Children in the control group were treated with conventional treatments such as nasal catheter oxygen inhalation, and those in the study group were treated with early CPAP. After 1 day of treatment, the blood gas indexes such as oxygen saturation(SaO₂), arterial partial pressure of oxygen［p(O₂)］, partial arterial carbon dioxide pressure［p(CO₂)］ and hydrogen ion concentration index(pH value)before and after treatment were compared between the two groups, and prognosis condition of the two groups was analyzed. Results After treatment, the levels of SaO₂, p(O₂)and pH value in the two groups were significantly increased, while the level of p(CO₂)was significantly decreased, and the study group had significantly higher levels of SaO₂, p(O₂)and pH value, and lower p(CO₂)than that in the control group(P<0.05). There was no significant difference in the incidence of complications between the two groups(P>0.05); the mortality rate in the study group was significantly lower than that in the control group, and the difference was statistically significant(2.94% vs. 20.59%, P<0.05). Conclusion Early CPAP is effective in treating severe pneumonia and respiratory failure in children, and it can promote improvement of blood gas index, effectively reduce incidence of complications and mortality, and promote - the prognostic recovery of children.