Abstract: OBJECTIVE To explore the prescription rules of professor Wang Canhui in treating chronic atrophic gastritis(CAG) through data mining. METHODS 305 medical records of 124 outpatients with chronic atrophic gastritis treated by professor Wang Canhui with good clinical outcomes were recorded. Both commonly used herds and herb categories were summarized by applying frequency analysis with SPSS 17.0 and also clustering analysis was done to excavate the coreprescriptions and commonly used herb pairs. RESULTS The top three herbs on the frequency list of herb use were deep-fried Atractylodes macrocephala Koidz， Radix Pseudostellariae and Curcuma zedoaria. The commonly used herbs are qi-tonification herbs， heat-clearing herbs， qi-regulation herbs and herbs for invigorating blood circulation and eliminating stasis， with two core prescriptions and four commonly used herb pairs being excavated. CONCLUSION Professor Wang Canhui focuses on protecting the vital qi of spleen and stomach when treating patients with chronic atrophic gastritis and advocates the method of tonifying spleen qi， clearing away depressed heat， regulating qi and blood.