The main difference between Alzheimer’s disease and cerebral atrophy is that Alzheimer’s disease is a class of diseases and cerebral atrophy is an imaging manifestation that can be seen in patients with Alzheimer’s disease. Alzheimer’s disease is defined as a condition in which people older than 60 years of age suffer from persistent and prolonged impairment of intelligence, thinking, memory, calculation, and emotion, as well as a decrease in their ability to perform their own activities and live their own lives. It usually includes Alzheimer’s disease and vascular dementia. Brain atrophy refers to the reduction of the volume of brain tissue structure, the reduction of brain parenchyma, the reduction of brain mass, and the reduction of the number of brain cells caused by various reasons. Imaging shows a series of changes such as flattening of the cerebral gyrus, widening and deepening of the sulci, and enlargement of the ventricles, cerebral pools, and subarachnoid space. It can be seen in normal aging, Alzheimer’s disease, vascular dementia, traumatic brain injury, and chronic cerebral ischemia. Thus Alzheimer’s disease can present with brain atrophy manifestations, but there are more causes of brain atrophy than just Alzheimer’s disease. If brain atrophy is found in imaging examination or intellectual, thinking or memory impairment occurs, it is recommended to consult a doctor in time to clarify the diagnosis and standardize the treatment to avoid delaying the condition.