Objective: To discuss some questions needed thinking highly and existed in diagnosis and treatment of dementia, so as to provide references for more accurate and reasonable diagnosis and treatment of dementia. Data sources: A computer-based online search of Medline database was undertaken for articles related to dementia, the clinical diagnosis and treatment of dementia and the problems, published in English between 1992 and 2005; meanwhile, we searched CNKI for Chinese papers about the treatment of dementia and its effect on cognitive function by using the key words of "dementia, cognitive impairment, diagnosis" in Chinese. Study selection: The data were selected firstly to exclude the repetitive studies and Meta analysis, and select the articles met the inclusive criteria and look up the full texts. Data extraction: A total of fifteen articles about clinical diagnosis and treatment of dementia and its problems were collected; twelve articles were included after excluding the repetitive or similar studies. Data synthesis: Dementia is a group of clinical symptom-complex characterized by cognitive function impairment; case history of patients is an important item for elemental etiological diagnose and classification of diseases in the clinical diagnose and treatment. But at the initial phase of disease, the psychiatric symptom is the more obvious, but not the cognitive function impairment. Dementia with depression and pseudodementia contributed to depression should be identified in clinical diagnose process. The therapic approaches of dementia mainly include etiological therapy, biological therapy, psychotherapy and so on. Moreover, in the biological therapy, selection of medicine should pay more attention to the category of medicine, toxicogenic effect and side effect. Usually various kinds of nouropsychological scales are used to understand the injury with different reasons and various regions, the psychological changes and psychological function still remained in different courses of disease. However, the estimated results from the scales are only regarded as the first diagnosis for dementia, but not the final diagnosis. Conclusion: Both the case history and psychiatric symptoms of dementia can impact the diagnosis. So it is necessary to expand the clinical visual angles and take notice to individualized features besides quantitating the diadynamic criteria, so as to constantly improve the accurate and systemic diagnosis and therapy of dementia.