Objectives Heart failure (HF)is one of the most common outcome for all kinds of heart diseases, the effects of energetic therapy on HF remains controversial, especially to ischemic HF. The aim of this study was to explore the effect of exogenous phosphocreatine with different concentration on L-type calcium(ICa-L) current in ischemic ventricular myocytes of guinea pig and to investigate its underlying electrophysiological mechanism for the treatment of ischemic HF. Methods Single ventricular myocytes were isolated enzymatically from left ventricle of guinea pig. Peak ICa-L current were recorded using patch clamp techniques in the whole-cell configuration when myocytes had been superfused with normal Tyrode solution, simple ischemic solution, ischemic solution containing phosphocreatine with different concentration for 10 minutes respectively. Results Peak ICa-L current density of myocytes superfused with simple simulated ischemic solution was remarkably inhibited by 80.6 ±5.2% compared with myocytes superfused with normal Tyrode solution(P＜0.05). Ischemic solution containing phosphocreatine of 5, 10, 20, 30mmol/L inhibited Peak ICa-L current density by (53.8±6.7)%, (41.8±8.2)%, (38.1±7.4)%, (36.6±9.7)% respectively.There was no statistical significance among phosphocreation of 10, 20, 30 mmol / L. Conclusions Extrogenous phosphocreatine could reverse the inhibition of ICa-L current under ischemic condition,which could be the ionic basis for the treatment of ischemic heart failure. 0～10 mmol/L phosphocreatine exerted significant dose-effect relationship which no longer existed as concentration more than 10 mmol/L.It is supposed that phosphocreatine increased ICa-Lcurrent by many pathways rather than simple substrate for ATP synthesis.