The common causes of postural hypotension are the following three: first, some primary ones, such as autonomic dysfunction, dopamine beta hydroxylase deficiency, familial autonomic dysfunction, and autonomic failure in multiple system atrophy. Second, secondary diseases cause. The common ones are chronic alcoholism, diabetes, malignant tumor, Parkinson’s disease, and vitamin B1 or B12 deficiency. Third, some other diseases. Such as hypovolemia, such as bleeding, burns or hemodialysis after hypovolemia, or dehydration, can cause postural hypotension. Postural hypotension can also occur in patients with poor hemodynamic regulation, such as the elderly, pregnant, febrile or bedridden for a long time. There are also drugs, such as antihypertensive drugs, insulin or tricyclic antidepressants, which can also cause postural hypotension.