The causes of hypertension at the age of 20 are as follows: 1, the age of onset is relatively young, most of which may be seen in some secondary hypertension. Secondary hypertension should pay attention to the presence of renal hypertension, to exclude the presence of nephritis, renal stones or renal artery stenosis caused by hypertension; 2, also pay attention to the presence of endocrine hypertension, including primary aldosteronism, Cushing’s disease, pheochromocytoma, etc., to do the CT of the adrenal glands, to check the aldosterone, check the renin-angiotensin in the prone position, and do the corresponding treatment; 3, if The above secondary factors are ruled out, it may also be a familial hypertension, that is, primary hypertension, to understand the family history, whether there is a history of hypertension in various members of the family.