Abstract: Sprague-Dawley rats were randomly divided into the normal group and ischemia/reperfusion(I/R) group.Isolated hearts were switched to the Langendorff mode and perfused with or without fatty acid.Coenzyme A(CoA)，acetyl CoA and adenine nucleotides(AMP，ADP and ATP) in heart tissues were analyzed by HPLC and lactate in heart tissues and fatty acid in perfusate were determined using the assay kit.The influence of danshensu and ranolazine on the above biomarkers were observed.Ranolazine significantly increased ATP and adenylate energy charge (AEC) of rat heart tissues and lowered lactate level as well as the ratio of acetyl CoA/CoA in rat heart tissues.Danshensu could also significantly elevate ATP and AEC values in heart tissues and lower lactate level in rat heart tissues.The ratio of acetyl CoA/CoA in I/R group with fatty acid were significantly decreased，which suggested that danshensu might inhibit myocardial fatty acid oxidation in ischemia/reperfusion rats in the presence of fatty acids.The results suggested that danshensu may partially improve myocardial energy metabolism of ischemia/reperfusion rats and protect against I/R injury of rat hearts.