Alzheimer disease （AD） is one of the most common neurodegenerative disease with a heavy disease burden. At present， the pathogenesis of AD is unknown. Therefore， there is a lack of disease modifying medicines that can reverse or delay the progress of AD. This paper describes the research on disease modifying pharmacological therapy based on the theory of main pathogenesis of AD. It includes the research using Aβ， tau or other biomarkers as targets and new clinical trials of old medicines. Among them， most trials terminated at a certain stage of the drug research and development process or clinical trial process， and some are still ongoing. The relationship between AD pathogenesis research and disease modifying therapy is mutual promotion and verification. The breakthrough of basic research may bring new hope to drug research and development. At the same time， the success or failure of clinical trial in a certain direction is a test of its theoretical basis. There is still a long way to go from the research on the pathogenesis of AD to the development of disease modifying medicines， and then to their widely clinical use.