Abstract: The mechanism of acoustic organ damage due to bypercholesterolemia in rabbits and diabetes in mouse was studied by ABR. hearing examination, biochemical study of the sera and histochemical observation of the inner ear. The results suggested that acoustic organ damage resulted from the activity descent of SDH,AchE and metabolic disorder in the inner ear during hypercholesterolemia. The cochlear and central nervous system damage might be related to hypercoagulability of blood in diabetes.