Objectives <p>To address the immune rejection and inflammatory reactions that currently exist in functional myocardial patches when promoting myocardial cell growth.</p> Methods <p>The cardiac acellular Decellularized Extracellular Matrix (dECM) hydrogel was prepared and used as a functional myocardial patch for immune rejection and inflammatory reaction.</p> Results <p>Compared with hyaluronic acid hydrogel and cardiomyocytes in tissue culture plate, the cardiomyocytes in the cardiac dECM hydrogel had the strongest cell viability. After 5&#xa0;days of culture, the cell viability increased to 292.9% relative to control. Moreover, after the hydrogel culture, the relative expression levels of <i>CACNA1C</i> and <i>ATP2A2</i> genes in cardiomyocytes reached 3.43 and 1.83, respectively, which were also higher than those in the other two groups.</p> Conclusions <p>From the above results, cardiac dECM hydrogel can promote the growth of cardiomyocytes.</p>