Myocardial infarction causes structural damage that impairs both the mechanical and electrophysiological functions of the heart. Modulating the mechanical and electrical properties of biomaterials represents a promising strategy for myocardial repair. This review systematically outlines the mechanisms and design principles of such regulation through three integrated approaches: mechanical modulation, electrical modulation, and mechano-electrical coordination. Mechanically, tuning stiffness, elasticity, and anisotropy enhances cellular alignment, tissue integration, and structural support. Electrically, regulating conductivity and anisotropy facilitates synchronous signal propagation and functional restoration. The coordinated strategy enables synergistic optimization of mechanical and electrical properties, thereby improving repair outcomes. Furthermore, biomimetic in vitro models, including cardiac organoids and heart-on-a-chip systems, provide physiologically relevant platforms for evaluating material performance. This review provides foundational insights and design principles for advancing myocardial repair via mechano-electrical biomaterial engineering.