Abstract: Dilated cardiomyopathy (DCM) is a group of heterogeneous diseases characterized by unilateral or bilateral enlargement of the cardiac cavity along with systolic dysfunction. DCM can be attributed to genetic and non-genetic etiologies. More than 40 pathogenic genes have been reported, including genes encoding sarcomere, cytoskeleton protein, ion channel, mitochondria, desmosomes, and so on. In recent years, great progress has been made in the mechanism of pathogenic genes, and the effects of environment, non-coding RNA, DNA methylation, and histone acetylation modification on the phenotype of the disease have been gradually recognized. Although the relationship between genotype and phenotype has not been fully elucidated, the exploration of the molecular mechanism focused on the genome-environment interaction provides clinicians with a deeper understanding of the disease. This review provides an overview of DCM with a focus on their genetic etiology and genome-environment interaction.