Dementia with Lewy bodies (DLB), also known as Lewy body dementia, is the second most commonly degenerative cause of dementia in the elderly. At present, there are few reports about DLB confirmed by autopsy in our country. The main clinical manifestations of the patient were progressive cognitive decline, intermittent mental and behavior disorder, visual hallucination, sensitive to antipsychotic drugs, and parkinsonism and/or autonomic nervous system dysfunctions along with the progress. Here we reported such 1 case. The results of autopsy pathology showed that α-synuclein positive Lewy bodies existed extensively in the cytoplasm of cortical and subcortical neurons, which verified the clinical diagnosis before the patient’s death. We hope to enhance the recognition of the disease and facilitate its early diagnosis through studying this case.