 Hypertension is one of the most common cardiovascular diseases, which is a major risk factor for stroke and cardiovascular events. Accumulated data has shown that target-organ damage is related not only to 24-h mean intra-arterial BP, but also to BP variability BPV in subjects with essential hypertension. There are many studies about the effects of different kinds of drugs on blood pressure, but the clinical researches about the impacts of antihypertensive drugs on BPV are limited, and the conclusion is still controversial. 