The standard of normal blood pressure is that systolic blood pressure is lower than 140mmHg and diastolic blood pressure is lower than 90mmHg, which is called normal blood pressure. Among people with normal blood pressure, the risk of cardiovascular disease is different in ten years according to the inconsistency of blood pressure. People with normal blood pressure are divided into two groups: normal hypertension and normal blood pressure, in which normal blood pressure means that systolic blood pressure is lower than 1.20 mmHg and diastolic blood pressure is lower than 80mmHg. Normal hypertension refers to systolic blood pressure 120- 139mmHg and/or diastolic blood pressure of 80-90mmHg, which is called normal hypertension.