Objective To study the protective function of ?-blockers to injury myocardial cell after PCI.Methods 60 cases were divided into two groups randomly,group A(30 cases) was control group,group B(30 cases) took ?-blockers orally before PCI.Serum levels of CK-MB were measured in 60 cases undergoigg coronary interventions in preprocedure,1st hour and 6th hour after operation,we judged the effect of ?-blockers.Results No difference was found in proprecedural level of CK-MB of two groups.There was significant difference between group A and group B 1h and 6h after operation(P=0.012 and 0.002).In the control group,we saw that the levels of postoperative CK-MB were higher than preprocedure (P=0.033 and 0.022).In hospital MACE did not occur in both groups.Conclution ?-blockers decrease the level of CK-MB in 30 cases undergoing coronary interventions.Thus it can decrease the mortality.