Ambulatory blood pressure monitoring (ABPM) is a non-invasive automated blood pressure monitor that measures blood pressure dynamically over a 24-hour period. Ambulatory blood pressure has the following advantages over incidental blood pressure: 1. It reflects blood pressure more objectively and realistically, and removes the chance of incidental blood pressure measurement. 3.Improve the detection rate of early asymptomatic mild hypertension. 4.Better guidance of drug treatment. 5.Predict the time of sudden onset of cardiovascular disease in a day. 6.Judging the prognosis of hypertension disease. 7.Provide an effective monitoring means for judging the efficacy of non-drug antihypertensive measures.