Abstract: Dilated cardiomyopathy (DCM) is the most common cardiomyopathy in children, its etiology is complex and the prognosis of different etiologies varies greatly, Accurate etiological diagnosis is conducive to individualized treatment of children. In recent years, with the application of second-generation sequencing, potential genetic-related causes of children with DCM have been continuously discovered, especially genes encoding sarcomere (TTN, MYH7, etc.) and cytoskeleton (DMD, DES, etc.) proteins. Nevertheless, no more than 40% of children with DCM can be diagnosed with a clear cause, and how to improve the diagnosis of the causes of DCM in children is also a huge challenge for pediatricians. The genetic research of adult DCM has made considerable achievements but at present, there are not many genetic studies on children’s DCM. Whole-exome sequencing (WES) is often used for genetic diagnosis, but for copy number variation (CNV) and intron mutations, whole-genome sequencing (WGS) is of more advantages. In the future, the development of new molecular detection technologies, including third-generation gene sequencing and miRNA, may change the current status of diagnosis of the causes of DCM in children. This article briefly summarizes the current status and predicaments of the diagnosis of children’s DCM under the background of current genetic etiology and provides clinicians with clearer ideas for accurate diagnosis of children’s DCM.