microRNAs are short regulatory RNAs that can regulate gene expression through interacting with the 3UTR of target mRNAs.Although the role of miRNAs has been extensively studied in adult human and animal models of heart disease,nothing is known about their expression in pediatric heart failure patients.[Objective]The purpose of this study is to determine if circulating miRNAs are useful diagnosis biomarkers in children with heart failure or dilated cardiomyopathy(DCM).[Methods]In this study,we analyzed children(0-14 years old)with heart failure admitted to pediatric cardiac center from Dec 2013 to Mar 2016.An array for miRNAs seq and real time polymerase chain reaction confirmation of select miRNAs were performed.To analysis the serum miRNA levels and the correlation between the left ventricular ejection fraction(LVEF),left ventricular diameters(LVDD),serum BNP level and whether the use of glucocorticoid treatment.At the same time,compared with the degree of heart failure in children with different levels of serum miRNA changes are different.[Result] five miRNAs were significantly up-regulated(hsa-miR-26,hsa-miR-27,hsa-miR-126,hsa-miR-142,hsa-miR-143)and 0 miRNAs were down-regulated in patients with DCM [Conclusion] We identified specific miRNAs that are differentially regulated between children with DCM compared with heath children.