Abstract: The plasma ANF, high share rate, low share rate and plasma relative viscosity of 73 subjects with angiocardiopathy or cerebrovascular disease are determined, The result shows all present significantly higher than normal people (P<0. 01). It is valuable to measure them for observing the condition of the patients. By correlation analysis, the plasma ANF is significantly correlative with the high share rate, the plasma relative viscosity and the serum cholesterol(r=0. 254, 0. 320, 0. 261 ). The mechanism is discussed that the exacerbated load of heart by increase of blood viscosity and enlarged blood volume by change of osmotic pressure, in addition, hypoxia and slight carbon dioxide retention, can stimulate the synthesis and release of ANF. The reason for positive correlation between the plasma ANF contents and serum cholesterol is probably that ANF can inhibit the change from endogenous cholesterol to pregnenolone.