Abstract: Objective: To observe the changes of blood gas level and myocardial enzymology in children with severe pneumonia. Methods: The changes of the electrocardiogram,blood gas level and myocardial enzymology in 58 children with severe pneumonia were analyzed retrospectively; and the correlations among them were studied. Results: The level of blood gas analysis in the group with abnormal myocardial enzymology was obviously higher than that with normal myocardial enzymology( P 0. 01); There was a positive correlation between the level of blood gas analysis(-BE) and myocardial enzymology( CK-MB) in the 32 cases with abnormal myocardial enzymology( P 0. 01). Among the 58 cases of severe pneumonia,51 presented great changes in electrocardiogram,32 of whom were in the group with abnormal myocardial enzymology( 62. 75%); 11 cases were accompanied by heart failure( 18. 97%). Conclusions: Hypoxemia and metabolic acidosis facilitate the genesis and development of myocardial damage. Early intervention could prevent the incidence of heart failure. Blood gas analysis,myocardial enzymology detection and electrocardiogram examination are beneficial to the early diagnosis and prognosis of myocardial damage in children with severe pneumonia.