Alzheimer’s disease is mainly categorized into three stages, i.e. the mild stage, the moderate stage and the severe stage, and there are differences in the symptoms shown by patients in different periods, including memory loss, decline in speech function, personality change, mental abnormality and so on. 1. Mild stage: mainly manifested as memory impairment, such as memory loss of recent events, usually forgetting some daily objects or some things that should be done in daily life. Along with the gradual progress of the disease, distant memory loss can gradually appear, that is, forgetting things that have happened for a long time. Some patients may also suffer from visual and spatial impairment, such as not being able to find their way home after going out. 2. Moderate stage: This stage of dementia is characterized by a significant increase in memory impairment, a decrease in the ability to make social contacts and learn new knowledge, as well as a decrease in repetitive speech and logical thinking ability. In severe cases, there may be loss of recognition, loss of use and aphasia. In addition, some patients may have personality changes, such as mental abnormality, irritability or reticence. 3. Severe stage: Alzheimer’s patients in this stage often show significant memory loss, loss of speech, crying and laughing, emotional indifference, and even loss of basic self-care abilities such as eating and dressing. In addition, some patients may experience symptoms such as tetraplegia and paralysis. When the symptoms of Alzheimer’s disease appear, attention should be paid to it, seek medical treatment as soon as possible, and after a clear diagnosis is made by perfecting relevant examinations, actively cooperate with the doctor for treatment, so as to prevent delays in the condition.