 Hypertension is one of the most common cardiovascular diseases, which is a major risk factor for stroke and cardiovascular events. Traditionally, cardiovascular risk stratification in hypertensive patients was based on the average blood pressure BP measured in the clinic. 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. Growing evidence demonstrated that BPV has considerable prognostic value for all-cause mortality and cardiovascular outcomes, independent of average BP. At present, the normal range of BPV is not very clear. 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. 