The aim of this study was to investigate whether punicalagin (PU) could prevent obesity-related cardiac dysfunction by promoting DNA demethylation, and to explore its possible mechanism. C57BL/6J mice were fed with standard diet, high-fat diet (HFD), HFD supplemented with resveratrol, low-dose PU (LPU) and high-dose PU (HPU) for 8 weeks. Compared with HFD group, body weight was signif icantly lower in PU treatment groups, number of cardiomyocytes and the protein level of myosin heavy chain 7B were signif icantly higher in PU treatment groups. Levels of 5-hydroxymethylcytosine and 5-formylcytosine were signif icantly lower in HFD group than in other groups. Compared with the HFD group, the protein level of ten-eleven translocation enzyme (TET) 2 was significantly higher in PU treatment groups, p-AMP-activated protein kinase (AMPK) was signif icantly higher in LPU group. Levels of total antioxidant capacity and the protein levels of complexes Ⅱ/Ⅲ/Ⅴ, oxoglutarate dehydrogenase, succinate dehydrogenase B and fumarate hydrolase were signif icantly lower in HFD group than PU treatment group. The ratio of (succinic acid + fumaric acid)/α-ketoglutarate was signif icantly higher in HFD group than other groups. In conclusion, PU up-regulated TETs enzyme activities and TET2 protein stability through alleviating mitochondrial dysfunction and activating AMPK, so as to promote DNA demethylation, thus preventing obesity-related cardiac dysfunction.