Cardiovascular diseases are the leading cause of morbidity and mortality throughout the world underlining the importance of efficient treatments including disease modeling and drug discovery by cardiac tissue engineering. However, the predictive power of these applications is currently limited by the immature state of the cardiomyocytes. Here, we developed gelatin hydrogels chemically crosslinked by genipin, a biocompatible crosslinker, as cell culture scaffolds. Neonatal rat cardiomy-ocytes appear synchronous beating within 2 days after seeding on hydrogels. Furthermore, we applied the electrical stimulation as a conditioning treatment to promote the maturation of cardiomyocytes cultured on the hydrogels. Our results show that electrical stimulation improves the organization of sarcomeres, establishment of gap junctions, calcium-handling capacity and propagation of pacing signals, thereby, increase the beating velocity of cardiomyocytes and responsiveness to external pacing. The above system can be applied in promoting physiological function maturation of engineered cardiac tissues, exhibiting promising applications in cardiac tissue engineering and drug screening.