[Abstract] Objective To investigate the aging change of proportion of blood flow to the brain from the heart and corresponding influential factors in healthy subjects. Methods In present study, 140 healthy subjects out of health examination population were recruited. Their cerebral blood flow and cardiac output were measured by Color Doppler Ultrasound. The related characteristics and hemodynamics were also recorded and determined. Data were analyzed by linear correlation and regression. Results The proportion of blood flow to the brain decreased at a rate of 1.3% per decade. This proportion is higher in women than men (18.68%±6.15% vs. 13.23%±4.93%, P<0.01). The linear correlation showed that BMI, blood pressure, pulse wave velocity and cerebrovascular resistance were negatively related with this proportion (P<0.001); whereas BMI was the only independent associated factors after multiple regression (β=-0.311，P<0.01). Conclusions In healthy population, the proportion of blood flow to the brain decreased with aging, which is higher in women and negatively associated with BMI.