Abstract: Objective To study the molecular pathologic mechanism of myocardial cell apoptosis irradiated by microwave.Methods Myocardial cells irradiated by pulse microw ave at power density 950mW/cm².The irradiation time was 0,30,60,120s respectively.T hen mo rphologic changes of cells were observed by inversion microsco pe,and the apoptosis rate was examined by flow cytometer and the method of TUNEL,and expression changes of many relevant apoptosis genes were investigated by immunohistochemical method.Results Myocardial cells appeared representative apoptosis image after irradiation.Apoptosis rates were(36.76±5.31)and(26.44±3.94)respectively at 6 h and 24 h after irradiation.There was mar ked statistical discrepancy compared with control group(2.36±0.87)(P<0.01).The results of TUNEL indicated the dosage-effect relationship between apoptosis and irradiation dosage.The expression of Bax,P53,and -cmyc enhanced obviously (P<0.01),and Bcl-2 enhanced transitorily,and then reduced obviously(P<0.01).Conclusion Myocardial cells were susceptive to microwave irradiation.The irradiation could induce apoptosis of myocardial cells,which appeared the dosage-effect relationship.Bcl-2/bax,p53 and -cmyc were concerned with apoptosis and played impor tant roles.