Dementia is a disease associated with old age, the incidence of which is increasing as our population ages. Since patients with dementia often lose the ability to take care of themselves, these diseases impose a heavy financial burden and great mental stress on the patients themselves, their families and society. Dementia is a slowly progressive disease. If a patient has already been diagnosed with dementia, there is no way to recover from the disease, but only to control the symptoms with medications, and these medications cannot prevent the further development of dementia at present. Therefore, early prevention of dementia is particularly important. After years of research, Nanjing General Hospital of Nanjing Military Command has found that the incidence of dementia can be significantly reduced by changing the bad lifestyle, effectively controlling the risk factors and actively treating the related diseases. Many people incorrectly believe that dementia is a disease of the elderly, so only people of age are necessary to prevent dementia. This is not the case. Like many other chronic diseases, dementia occurs as a result of years of exposure to risk factors. In other words, it takes many years for the effects of risk factors to accumulate before they cause the onset of the disease. Therefore, the earlier dementia is prevented, the better. Research has shown that conditions at birth and even during life may influence the onset of dementia later in life. A follow-up study in the United States showed that low birth weight was associated with the development of dementia in adulthood. Therefore, prevention of dementia may begin during pregnancy. It is important to pay attention to balanced nutrition and appropriate activities, and to have regular medical checkups during pregnancy and childbirth. From birth to the preschool stage, children should also pay attention to balanced nutrition, choose age-appropriate food, and breastfeeding is also important during this critical period. This stage is also a period of rapid development of the nervous system, attention should be paid to appropriate pre-school education, to create a rich external environment to promote the development of the nervous system. Of course, pre-school intellectual development needs to be combined with the physiological and psychological characteristics of the child, the right amount at the right time. If the development is not scientifically advanced or overloaded, it may ultimately be counterproductive. Childhood and adolescence are important periods of neurological development and growth, and it is important to adopt good personal habits at this stage. This includes diversifying the diet, reducing the intake of foods containing lead and aluminum, etc., not smoking and not abusing alcohol. In terms of life, maintain sufficient sleep and regularity of life, cultivate one’s hobbies and interests, actively participate in mental and physical exercises, maintain an optimistic mood, and cultivate good study and thinking habits so that the brain function can be fully developed and exercised. Middle age is the period of development of risk factors for diseases such as cerebrovascular disease and dementia. This period is often the time when diseases such as hypertension, diabetes and hyperlipidemia are formed. Therefore attention should be paid to the prevention of these diseases. Measures include reasonable control of salt, sugar and fat intake, regular physical exercise, and appropriate recreational activities to reduce physical and mental stress. In addition, regular monitoring of blood pressure, blood glucose, blood lipids and other indicators has been timely detection and treatment of these diseases. Old age enters the period of high incidence of dementia and cerebrovascular disease, and this period should focus on the prevention of dementia and cerebrovascular disease itself. The main measures include active control of risk factors such as hypertension, diabetes mellitus and high blood lipids. Regular checkups of cerebrovascular status and brain function should be carried out to detect abnormalities early and start treatment as soon as possible. Research conducted by Prof. Xu Green and others at Nanjing Military Region General Hospital shows that a large proportion of patients with cerebrovascular disease (stroke) develop dementia. Dementia can often be prevented by timely treatment of vascular disease, such as treating stenosis with stents. Their results of this study were recently published in a European medical journal.