Abstract：Objective：To study the medication rule of WANG Fu in using formulas to treat gastric cancer based on data mining technology. Methods： The outpatient formulas of WANG Fu Jingfang in treating gastric cancer were collected via the Outpatient Big Data System of WANG Fu's Formulas. The formula database was established via Excel， and analysis of association rules and clustering were carried out by SPSS Modeler18.0， Cytoscape and R language software. Results： A total of 515 formulas in treating gastric cancer by WANG Fu were included，involving 109 kinds of Chinese herbs，and the cumulative use of Chinese herbs was 8 197 times. The most frequently used Chinese herbs were Ginseng Radix et Rhizoma，Glycyrrhizae Radix et Rhizoma，Pinelliae Rhizoma，Scutellariae Radix and Coptidis Rhizoma. The main herbal effects were supplementing deficiency，clearing heat，dissolving phlegm and relieving cough as well as relieving panting. Warm herbs were more than cold herbs and neutral herbs， and in terms of channel entry，the spleen，stomach and lung channels were the most. The herbs obtained by association rules were all core drugs of Banxia Xiexin Decoction， and five basic formulas for treating gastric cancer were obtained by cluster analysis. Conclusion：When WANG Fu uses formulas to treat gastric cancer，he applies both attack and supplementation， simultaneous treatment with cold and warm herbs， and combination of yin and yang. He usually uses basic formulas including Banxia Xiexin Formula，and combines with herbs of eighteen antagonisms， such as Ginseng Radix et Rhizoma-Veratri Nigri Radix et Rhizoma， Aconiti Lateralis Radix Praeparata-Pinelliae Rhizoma， Sargassum-Glycyrrhizae Radix et Rhizoma， which provides inspiration and guidance for further exploring the application value of formulas in treating gastric cancer.