The difference between left and right hand blood pressure measurements of normal people is generally maintained at about 10 to 20mmHg as the normal value. In the measurement of blood pressure, the measurement of different time periods, the blood pressure value is also different results, the general systolic blood pressure to maintain at 90 ~ 140mmHg, diastolic blood pressure to maintain at 60 ~ 90mmHg is the normal range of values, however, the right hand’s blood pressure will be higher than the left hand’s blood pressure is slightly higher than the left upper limb, usually left and right hand blood pressure measurement of the difference between the value of the general to maintain at about 10 ~ 20mmHg is normal. If the difference between the blood pressure of the right and left hands is greater than 20mmHg, it is necessary to consider whether there are diseases of the arteries of the upper limbs, which may lead to a large difference in blood pressure, such as atherosclerotic plaques in the subclavian or brachial arteries, which lead to narrowing of the blood vessels, and this will lead to a significant decrease in blood pressure. A large difference in blood pressure between the right and left hands may also be caused by emotional excitement, high ambient temperature, after exercise, etc., and will usually return to normal within a short period of time. Therefore, if the difference between the blood pressure of the right and left hands appears abnormal for a long time, you should go to the hospital in time to find out the cause of the disease and treat the symptoms.