Xia Lei,1,* Hongdan Xu,2,* Yan Wang,3 Hainan Gao,4 Deping Zhao,4 Jinfeng Zhang,4 Ziyue Zhu,4 Kun Zuo,4 Ying Liu,3 Xiaoliang Li,3,5 Ning Zhang4 1Jiangsu CM Clinical Innovation Center of Degenerative Bone & Joint Disease, Wuxi TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Wuxi, 214071, People’s Republic of China; 2Department of Pharmacy, Wuxi Higher Health Vocational Technology School, Wuxi, 214000, People’s Republic of China; 3Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Provincial Key Laboratory for Research and Development of Tropical Herbs, Haikou Key Laboratory of Li Nationality Medicine, School of Pharmacy, Hainan Medical University, Haikou, 571199, People’s Republic of China; 4College of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin, 150040, People’s Republic of China; 5Key Laboratory of Tropical Cardiovascular Diseases Research of Hainan Province, Cardiovascular Diseases Institute of the First Affiliated Hospital, Hainan Medical University, Haikou, 571199, People’s Republic of China*These authors contributed equally to this workCorrespondence: Ning Zhang, College of Pharmacy, Heilongjiang University of Chinese Medicine, No. 24, Heping Road, Xiangfang District, Harbin, Heilongjiang Province, 150040, People’s Republic of China, Email zhangning0454@163.com Xiaoliang Li, College of Pharmacy, Hainan Medical University, No. 3 Xueyuan Road, Longhua District, Haikou City, Hainan Province, 571199, People’s Republic of China, Email lixiaoliang-1984@163.comPurpose: To elucidate the potential mechanisms of QFY for the treatment of Alzheimer’s Disease (AD), and explore the effective substances of QFY.Materials and Methods: UPLC-LTQ-Orbitrap-MS was used to identify the chemical constituents of the serum samples and the cerebrospinal fluid samples of rats after QFY administration. Network pharmacology was used to predict potential targets and pathways of QFY against AD. The AD mice model was established by subcutaneous injection of D-gal for 8 consecutive weeks. New object recognition (NOR) and Morris water maze test (MWM) were used to evaluate the learning and memory abilities of mice. Moreover, the levels of TNF-α, IL-1β, and IL-18 in the brain hippocampus of mice were determined by ELISA. The expression of Bax, Bcl-2, Caspase-1, PSD95, SYP, ICAM-1 and MCP-1 proteins in the hippocampus was detected by Western blotting. Furthermore, qRT-PCR was used to detect the gene expressions of PSD95, SYP, M1 and M2 polarization markers of microglia, including iNOS, CD16, ARG-1, and IL-10 in the hippocampus.Results: A total of 51 prototype compounds were detected in rat serum and 15 prototype components were identified in rat cerebrospinal fluid. Behavioral experiments revealed that QFY significantly increased the recognition index, decreased the escape latency, increased the platform crossing times and increased the residence time in the target quadrant. QFY also could alleviate the ultrastructural pathological changes in the hippocampus of AD mice. Meanwhile, QFY treatment suppressed the expression of inflammatory factors, such as TNF-α, IL-1β, and IL-18. QFY improved the synaptic plasticity of the hippocampus in D-gal model mice by significantly increasing the expression of proteins and mRNAs of PSD95 and SYP.Conclusion: QFY could effectively improve the learning and memory impairment of D-gal-induced AD mice by inhibiting the excessive activation of microglia, enhancing the expression of M2 microglia, inhibiting the increase of inflammatory factors, cell adhesion factors and chemokines, anti-apoptosis, and improving synaptic plasticity.Graphical Abstract: Keywords: Qi-Fu-Yin, Alzheimer’s disease, D-galactose, microglia phenotype, neuroinflammation