Aim To evulate the value of 12-lead holter in the diagnosis of coronary artery diseases. Method 60 cases were assessed by 12-lead holter and coronary angiography. Postive standard of 12-lead holter was ST-segment horizontal or downward sloping depression of greater than 1 mm (0.1 mV) at least 60 ms after the J point 80 ms in near two leads. Postive standard of coronary angiography was stenosis of coronary artery diameter reduction more than 50 percent than near normal vessel. Results ST-segment horizontal or downward sloping depression of 56 branches stenosis in 32 cases reaches postive standard,postive rate is 69.64% (p<0.05). In 35 branches of stenosis diameter is lower than 50%,only 9 cases ST-segment horizontal or downward sloping depression reaches postive standard, false postive rate is 25.7%. Conclusions 12-lead holter has an important value in diagnosis coronary artery disease,espically in aging and severe coronary artery disease.