The reason why the blood pressure of the right upper limb is higher than that of the left upper limb may be a normal physiological phenomenon, or it may be caused by multiple aortitis or congenital arterial malformation and other diseases. 1. Normal physiological phenomenon: Because of the anatomical position of the right and left brachial arteries, the blood pressure of the right upper extremity is generally higher than that of the left upper extremity, with a difference of 10-20mmHg, which is a normal physiological phenomenon. 2. Multiple aortitis or congenital arteriovenous malformation: If multiple aortitis or congenital arteriovenous malformation occurs in the head-arm trunk artery, right subclavian artery and distal arteries, it can cause localized vascular obstruction or stenosis, which leads to higher blood pressure of the right upper limb than that of the left upper limb. If the blood pressure of the right upper extremity is higher than that of the left upper extremity by more than 20mmHg, attention should be paid to timely consultation, identify the cause of the disease, and follow the doctor’s instructions for further treatment or therapy.