Objective:To explore the molecular mechanism of Polygalae Radix - Acori Tatarinowii Rhizoma medicinal pair for depression and Alzheimer disease (AD) with the same treatment through network pharmacology. Methods:Effective components of Polygalae Radix - Acori Tatarinowii Rhizoma medicinal pair were retrieved from TCMSP, TCMID and ETCM databases. The disease targets of depression and AD were retrieved from GeneCards, TTD and CTD databases. Targets of action of drugs on active components were predicted through SwissTargetPrediction, and then the intersection targets of medicinal pair and the diseases were taken. Cytoscape 3.6.1 was used to construct the interaction network of Polygalae Radix - Acori Tatarinowii Rhizoma medicinal pair on "component-common target-disease". The enrichment analysis of GO function and KEGG pathway was carried out with the help of Metascape platform, and molecular docking verification was carried out. Results:Through searching the databases and literature, 78 compounds in Polygalae Radix - Acori Tatarinowii Rhizoma medicinal pair were obtained, corresponding to 41 targets of different diseases with the same treatment. The GO function was mainly concentrated in response to lipopolysaccharide and cellular response to nitrogen compound. The KEGG pathway was mainly concentrated in lipid and atherosclerosis, calcium signaling pathway, serotonergic synapse, insulin resistance and so on. The core targets were PTGS2, ESR2, etc. Molecular docking showed that most of the core components could form stable conformation with the core targets. Conclusions:Polygalae Radix - Acori Tatarinowii Rhizoma medicinal pair has the characteristics of multi-component, multi-target and multi-pathway in the same treatment of depression and AD. Through their core components of senegenin, 1-carbobutoxy-β-carboline, 6-hydroxy-1,2,3,7-tetramethoxyxanthone, kaempferol and etc., the pair can act on PTGS2 and other targets, regulate lipid and atherosclerosis, calcium signaling pathway, serotonergic synapse, insulin resistance and so on, and play a therapeutic role in depression and Alzheimer's disease with the same treatment.