Aim To observe the changes in carotid arteriosclerosis plaque formation and injury between External Counterpulsation(ECP) group and no ECP group.Methods 165 patients(1-9 years) in treatment group by ECP and 68 patients without treatment were checked in carotid arteries with echo Doppler examination.Results Vessel wall injury in ECP group was 15.2% and carotid arteriosclerosis plaque formation was 11.5%.Vessel wall injury in no ECP group was 63.2% and carotid arteriosclerosis plaque formation was 51.5%.There were significant difference between the two groups(P<0.01).Conclusion ECP can reduce the incidence of vessel wall injury,preventing plaque formation.