Impairment in recognition of various properties of objects in space due to visual causes is called visual spatial perception impairment, or visuospatial dysfunction, and is one of the early symptoms of Alzheimer’s disease. Diagnosis of impaired visuospatial function: EEG changes in AD patients are not specific, and CT and MRI examinations show cortical brain atrophy and ventricular enlargement with widened sulci. Because many normal elderly people and other diseases can also develop brain atrophy, and some AD patients do not have obvious brain atrophy. Spect and positron emission tomography can show significant metabolic disturbances in the parietal-temporal contact cortex in AD, and possibly in the frontal lobe as well. The cause of AD is not known, so the diagnosis of dementia is made mainly on the basis of clinical manifestations, followed by a comprehensive analysis of the medical history, the characteristics of the disease course, the institutional examination of the spinal nervous system, psychological tests and auxiliary examinations, and the exclusion of other causes of dementia before the diagnosis of AD can be made. The most commonly used test is the Suggestive State Examination, which is a very simple test tool. In addition, the Alzheimer’s Disease Scale is also an internationally used test tool. In terms of differential diagnosis, care should be taken to differentiate dementia from vascular, vitamin B deficiency, pernicious anemia, neurosyphilis, normal pressure hydrocephalus, brain tumors, and other primary brain lesions such as pikillosis and Parkinson’s disease. It should also be distinguished from pseudodementia and delirium caused by depression.