Abstract: Objective To explore the influence of mycoplasma pneumonia infection on Kawasaki disease children with coronary artery lesions.Methods Kawasaki disease children com-plicated with coronary artery lesions were enrolled and divided into observation group (complicated with pneumonia mycoplasma infection)and control group (not complicated with pneumonia my-coplasma infection).Heart function index,myocardial enzymes index and immune function index were detected and compared between two groups.Results E peak,E /A ratio,LVEDD,LVEF of observation group were lower than control group.LDH,AST,CK,CK-MB,cTnI content of observation group were higher than control group.IgG,IgM,IgA levels of observation group were lower than control group.Conclusion Mycoplasma pneumonia infection can cause heart function damage,increase cardiac enzyme elevation and impair immune function in Kawasaki disease chil-dren complicated with coronary artery lesions.In the clinical treatment,more attention should be paid to the supplement of immunoglobulin.