Abstract: Spleen deficiency and phlegm fluid are the pathological characteristics of Alzheimer's disease (AD). Based on the functional decline and memory, thinking, and cognitive impairments of AD patients at different age stages, as well as the relationship with spleen soil function, combined with the understanding of previous medical experts on this disease, it is proposed that spleen deficiency is the initial cause of AD, the endogenous production of phlegm fluid and the loss of spiritual transformation activity are important links in the progression of AD. Strengthening the spleen and resolving phlegm fluid are the basic treatment methods for AD, and Linggui Zhugan Decoction is a representative formula for intervening AD.