Dementia is a common disease in the elderly population, it still exists some barriers for clinical physicians to diagnose dementia.To make the clinical diagnosis and the differential diagnosis of dementia, clinical physicians currently need to make a synthesis based on history, symptoms, signs, neuropsychological testing and auxiliary examination, and seize the characteristic features of different dementia and follow various diagnosis thinking principles.According to the recent research advances at home and abroad in the diagnosis of dementia, the clinical diagnosis thinking of dementia which is readily available to clinical physicians will be introduced.