Brain atrophy is not the cause of Alzheimer’s disease, Alzheimer’s disease patients imaging examination can appear the manifestation of brain atrophy, but the onset is not due to brain atrophy. Cerebral atrophy cerebral cortex, brain lobe refers to a variety of causes of brain tissue structure volume reduction, brain parenchyma reduction, brain quality reduction, brain cell number reduction. It can be related to normal aging, ischemia, necrosis and degeneration of brain tissue. Cranial MRI or CT can show a series of changes such as flattening of the cerebral gyrus, widening and deepening of the sulcus, and enlargement of the ventricles, cerebral pools and subarachnoid space. Alzheimer’s disease refers to cognitive dysfunction in old age caused by various reasons, and common causes include Alzheimer’s disease and vascular dementia. Patients with Alzheimer’s disease often show brain atrophy manifestations on imaging in the middle and late stages of the disease. When brain atrophy is detected in imaging examinations or manifestations of cognitive decline occur, timely medical consultation and standardized diagnosis and treatment are needed to avoid delaying the condition.