A blood pressure of 115/66mmHg in the left upper extremity and 105/55mmHg in the right upper extremity is normal. The normal blood pressure of human body is systolic blood pressure＜120mmHg and diastolic blood pressure＜80mmHg. Because the anatomy of blood vessels on the left and right sides of the human body is not exactly the same, there is a certain difference between the blood pressure on the left and right sides of the body, but the difference in blood pressure of upper limbs of the two sides of the body is generally not more than 20mmHg. Therefore, the blood pressure of the left side of the upper limb is 115/66mmHg, and the blood pressure of the right side of the upper limb is 105/55mmHg is normal. The left upper extremity blood pressure 115/66mmHg and the right upper extremity blood pressure 105/55mmHg are normal. When the bilateral blood pressure difference is greater than 20mmHg, then it is abnormal, seen in multiple aortitis, aortic coarctation, congenital arterial malformation and other reasons. Whether hypertensive patients lower blood pressure to meet the standard, should be the high blood pressure side shall prevail, if the blood pressure fluctuation or bilateral blood pressure difference is significant, should immediately go to the regular hospital to avoid delaying the condition.