Objective:To observation the protective effects of Custodiol HTK solution on myocardium in cardiac operation.Methods:50 patients of coronary artery bypass grafting and valves replacement were perfused 5 ~ 8℃C HTK solution at 30 ~ 40ml/kg after aortic clamping.Spontaneous resuscitation rate,serum electrolytes and blood gas analysis during CPB,intraday electrocardiogram,application of IABP postoperatively,the requirement for inotropics at 2 hours after the end of CPB,time of intubation and length of stay in ICU were also evaluated.