20 years old systolic blood pressure less than 120mmHg and diastolic blood pressure less than 80mmHg is normal blood pressure. Normal blood pressure includes systolic blood pressure and diastolic blood pressure, the normal value of blood pressure is regardless of gender and age, systolic blood pressure is less than 120mmHg, diastolic blood pressure is less than 80mmHg for normal blood pressure. Measurement of blood pressure at the age of 20 is not normal, its influence factors are more, physiological reasons such as long-term anxiety, excitement, mental stress, strenuous exercise, etc., pathological reasons such as diabetic nephropathy and renal artery stenosis caused by renal vascular hypertension, and so on. 20 years old should also adjust the state of life, correct bad dietary habits, should not be high sugar, high fat, high cholesterol diet, usually also want to control weight, try to avoid obesity and overweight, appropriate sports exercise, to maintain a standard body weight at the same time to enhance the body’s immune system, is also conducive to the control of blood pressure. It is recommended to go to a regular hospital to measure blood pressure, the measured value will be more accurate.