Mild cognitive impairment is a critical state between normal aging and dementia, characterized by the patient’s age-inappropriate memory loss and other mild impairments in cognitive function, but daily life is not affected, and does not meet the diagnostic criteria for dementia. It is common to see elderly people who remember past events clearly but cannot remember new events. For example, the elderly say, “Now I forget everything I say”, “I often can’t find where I put xxxx”, “I can’t call the name of an acquaintance”, “I can’t remember If this happens every day or more than 4~5 times a week, it is pathological and the chance of developing dementia is several times higher than normal elderly people. Cognitive impairment includes: (1) memory impairment (often considered an early symptom) such as: memory of recent events, memory of personal experiences, memory impairment of significant life events; (2) orientation impairment, including confusion about time, place, and people; (3) language impairment, including difficulty finding words, difficulty reading, writing, and understanding; (4) impaired visuospatial ability; (5) decreased numeracy; (6) decreased judgment (6) decreased judgment and problem-solving skills. Patients with MCI are at a significantly higher risk of developing dementia, and preventive intervention is important. Studies have found that approximately 10-30% of patients with MCI develop dementia each year, and that 2/3 of patients with dementia develop dementia from MCI, while only 1%-2% of normal older adults develop dementia each year. MCI is easy to ignore because it does not affect daily life very much. By the time the patient and family members feel the abnormality, the dementia is often mild or moderate. Dementia is closely related to hypertension, stroke, hyperlipidemia, cerebral white matter osteoporosis, diabetes, age, smoking, alcoholism, and low education level. Therefore, when elderly people develop memory impairment with the above mentioned diseases, they should go to the hospital promptly to see a specialist for head CT, MRI, TCD, neuropsychological testing and other related examinations to intervene early and delay the onset of dementia.