Abstract: Objective:To study the effect of fructose 1,6-diphosphate（FDP） preconditioning on energy metabolism during ischemia reperfusion in isolated rat hearts.Methods:The experiments were carried out in in isolated Langendorff-perfused rat hearts.After 10min preconditioning with Krebs-Ringer（containing oxygen-balanced）,ischemia period 20min followed by 20min reperfusion.A similar experimental protocol was repeated in the presence 5 mmol·L^-1 FDP throughout the different perfusion conditions.At the end of each step（preconditioning ischemia reperfusion）,the ATP were determined by ion-pair reversed-phase HPLC methods on ventricle homogenates from 48 rat hearts（8 hearts for each period both for control and FDP preconditioning hearts）.Results:FDP preconditioning could obviously increase ATP during ischmia and reperfusion（P＜0.001,P＜0.05）versus control;ATP during ischmia were obviously decrease versus period of preconditioning in control group（P＜0.001）.Conclusion: FDP preconditioning could enhance the concentrations of ATP on isolated ischemia reperfusion rat hearts model.It can improve energy metabolism of myocardial.