Objective To investigate the efficacy and mechanism of injectable conductive hydrogel Polypyrrole⁃Chitosan（PPY⁃CHI）on long⁃term improvement of cardiac function after chronic myocardial infarction. Methods PPY⁃CHI，a conductive complex，was synthesized by coupling Polypyrrole to a Chitosan（CHI）back⁃ bone. A rat chronic myocardial infarction model was constructed in vivo，post⁃infarction SD female rats were ran⁃ domly divided into three groups（PPY⁃CHI，CHI and Saline groups，n = 5）. PPY⁃CHI was implanted in and around the infarct area four weeks later. Long⁃term improvement in cardiac function was assessed by ultrasound，Masson staining，immunofluorescence and myocardial resistivity. Results After 22 weeks of transplantation of the bioma⁃ terials，in vitro evaluation revealed that intracardiac injection of PPY⁃CHI had lower tissue resistance ，greatly increased capillary density，significantly increased ventricular wall thickness in the scar area，and a（10.6 ± 0.55）% increase in LVFS compared to post ⁃infarction compared to CHI and Saline injections. Conclusions Intracardiac injection of PPY ⁃CHI promoted angiogenesis，reduced tissue resistance in the scar region，and inhibited adverse ventricular remodeling，which enhancethe recovery of cardiac function after chronic infarction.