There are many reasons for unstable blood pressure, often related to mental factors, environmental factors, poor lifestyle, cardiovascular disease and so on. 1. Mental factors: mental tension, stress, emotional excitement, etc., can cause blood pressure instability, high and low. You need to relax, keep your mood relaxed, and avoid mental stress to stabilize your blood pressure. 2. Environmental factors: in summer, due to the rise in temperature can make the whole body blood vessel expansion, or a lot of sweating, thus causing the blood pressure to lower, winter cold season, due to the whole body blood vessel constriction can make the blood pressure rise, need to pay attention to the summer heat, winter cold to keep warm. 3. Bad lifestyle: such as staying up late, smoking and drinking, high salt diet, overwork and so on, can make blood pressure unstable, need to change the bad lifestyle, so that the blood pressure to maintain stable. 4. Cardiovascular diseases: for example, coronary heart disease, arrhythmia, cardiac insufficiency patients, can cause unstable blood pressure fluctuation. Need to actively treat the primary disease, high blood pressure to take antihypertensive drug therapy, such as nifedipine extended-release tablets, ACEI drugs enalapril and so on. Therefore, if unstable blood pressure occurs, it is necessary to take appropriate treatment measures according to the specific situation, control the blood pressure, and prevent the occurrence of cardiovascular and cerebrovascular diseases.