Stroke is one of the leading causes of mortality.The risk factors for stroke include hypertension,coronary heart diseases,diabetes and obesity[1],in which hypertension is the top risk factor.Worldwide,hypertension is the leading preventable risk factor for death;and causes 54% of strokes[2].While stroke is one of the leading causes of mortality in the industrialized countries,the effects of elevated blood pressure on the Asian population also raise a concern.As in 2002,hypertension affects almost 20% of the population of China,which amounts to 160 million people[3].Moreover,stroke is the major complication of hypertension in Chinese population[3].Chinese Medical Association reported 3 million stroke deaths in 2009,more than twice that of 1985[3].