The core prescriptions and formulation characteristics in the treatment of edema by traditional Chinese medicine(TCM) masters were analyzed through data mining and their mechanisms were explored by network pharmacology. We collected journal reports on the treatment of edema by TCM masters in three sessions from China National Knowledge Infrastructure(CNKI) and constructed a database by Traditional Chinese Medicine Inheritance Support System 3.0. The prescriptions in the case studies were analyzed by association rules and k-means clustering. The chemical components and targets of Chinese medicines in core prescriptions were collected through TCMSP and TCMID. Edema-related targets were collected from DrugBank and GeneCards. The protein-protein interaction(PPI) network was constructed by STRING and the core targets were screened out. FunRich 3.1.3 was used to enrich the expression sites of core prescriptions. Metascape was used to perform Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis of intersection targets. Cytoscape 3.6.0 was used to visualize the "Chinese medicine-active ingredient-core target-pathway" network. The results showed that 315 pieces of medical records in the treatment of edema by TCM masters were obtained and five core prescriptions were analyzed by association rules and k-means clustering. Core prescription 1 contained Poria, Atractylodis Macrocephalae Rhizoma, Astragali Radix, Alismatis Rhizoma, Glycyrrhizae Radix et Rhizoma, and Codonopsis Radix, involving 166 chemical components and 1 125 targets. Core prescription 2 contained Astragali Radix, Salviae Miltiorrhizae Radix et Rhizoma, Poria, Chuanxiong Rhizoma, Paeoniae Radix Rubra, and Angelicae Sinensis Radix, involving 138 chemical components and 1 112 targets. Core prescription 3 contained Poria, Salviae Miltiorrhizae Radix et Rhizoma, Astragali Radix, Atractylodis Macrocephalae Rhizoma, Alismatis Rhizoma, and Coicis Semen, involving 126 chemical components and 1 121 targets. Core prescription 4 contained Poria, Forsythiae Fructus, Atractylodis Macrocephalae Rhizoma, Imperatae Rhizoma, Cicadae Periostracum, and Coicis Semen, involving 58 chemical components and 820 targets. Core prescription 5 contained Poria, Atractylodis Macrocephalae Rhizoma, Astragali Radix, Alismatis Rhizoma, Trionycis Carapax, and Dioscoreae Rhizoma, involving 68 chemical components and 919 targets. The core targets of core prescriptions included AKT1, ALB, CASP3, MAPK3, EGFR, SRC, MAPK1, and TNF. The potential targets of core prescriptions in the treatment were highly expressed in the stomach, bladder, lung, and kidney. KEGG pathways were enriched in inflammation and cell cycle pathways, especially the inflammation-relation pathways. The therapeutic effect of core prescriptions on edema is presumedly achieved by tonifying the spleen, draining water, activating blood, and benefiting Qi to resist inflammation and regulate the immune system. This study is expected to provide references for the summary of TCM masters' experience and new drug development.