HiPSC-CMs have been successfully differentiated into beating cardiomyocytes with high efficiencies [1].The main limitation is that most of the generated cardiomyocytes are immature compared with adult cardiomyocytes and exhibit fetal-like gene expression[2,3].Organized cardiomyocytes alignment is critical to the mechanical properties of the heart [4,5].In this study,we fabricated a simple PDMS chip with surficial repetitive elongated convex hexagons, which recapitulate the cellular organization of native heart tissue, to promote the elongation and alignment of hiPSC-CMs.The hiPSC-CMs exhibited matured phenotype and enhanced contractility.The established heart on a chip is economical and of great potential in cardiac drug screening and toxicity testing.