A large pressure difference between high and low pressure is usually caused by atherosclerosis, heart valve insufficiency and other conditions. 1. Arteriosclerosis: aortic and large arteries sclerosis, resulting in reduced elasticity of blood vessels, in systole can not expand to accommodate more blood, resulting in increased systolic blood pressure, diastolic blood flow into the periphery during diastole is weakened, resulting in decreased diastolic blood pressure, the formation of high-pressure low-pressure pressure difference. 2. Incomplete closure of heart valves: Incomplete closure of heart valves causes diastolic blood pressure to fall and systolic blood pressure to rise, thus causing high pressure and low pressure difference. There may be other reasons for high pressure and low pressure difference, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.