Objective:To analyze the medication rule of traditional Chinese medicine in treating plasma cell mastitis based on data mining. Methods The relevant literatures of traditional Chinese medicine in treating plasma cell mastitis which published in the past 20 years were searched in the main Chinese literature database. After screening by relevant standards,the medication information of related prescriptions were collected to establish the database. The association rules,frequency analysis and other methods were used to perform data mining for compound recipes of Chinese materia medica,and the main drugs,the medication rule of couplet medicines and medicine group in the treatment of plasma cell mastitis were investigated.  Results: ①In the literatures of“recipes for general treatment”,Radix Bupleuri is the highest frequent used herb,followed by Herba Taraxaci,Radix Paeoniae Rubra. Medicine for clearing heat and removing toxicity and drugs with cold and cool in nature are the most commonly used. The couplet medicines with higher confidence include “Herba Ephedrae-Radix Rehmanniae Preparata”,“Fructus Trichosanthis-Flos Lonicerae”,the medicine group with higher confidence include“Radix Salviae Miltiorrhizae-Radix Paeoniae Rubra-Herba Taraxaci”and so on. The couplet medicines with higher reliability include“Radix Bupleuri-Radix Paeoniae Rubra”,“Radix Bupleuri-Herba Taraxaci”,the medicine group with higher reliability include“Radix Paeoniae Rubra-Herba Taraxaci-Radix Angelicae Sinensis”and so on. ②In the literatures of “treatment by stages”,in lump period Radix Bupleuri is the highest frequent used herb,followed by Herba Taraxaci,Herba Hedyotis；in abscess period Flos Lonicerae is the highest frequent used herb,followed by Herba Taraxaci,Radix Angelicae Sinensis；in fistula period Radix Angelicae Sinensis is the highest frequent used herb,followed by Radix Astragali seu Hedysari,Radix Salviae Miltiorrhizae；in perioperative period Radix Angelicae Sinensis is the highest frequent used herb,followed by Radix Paeoniae Rubra,Radix Bupleuri. Drugs with cold and cool in nature are the most commonly used through all periods,medicine for clearing heat and removing toxicity is the most commonly used in the periods of lump,abscess,fistula,while blood-supplementing medicine is the most commonly used in perioperative period. The couplet medicines with higher confidence include “Radix Curcumae-Radix Bupleuri”in lump period,“Herba Taraxaci-Radix Paeoniae Rubra”in abscess period,“Semen Sinapis Albae-roasted ginger”in fistula period,“Radix Paeoniae Rubra-Radix Angelicae Sinensis”in perioperative period；the medicine group with higher confidence include “Rhizoma Corydalis-Herba Taraxaci-Radix Bupleuri”in lump period,“Radix Salviae Miltiorrhizae-Radix Paeoniae Rubra-Herba Taraxaci” in abscess period,“Herba Hedyotis-Radix Salviae Miltiorrhizae-Radix Angelicae Sinensis”in fistula period,“Radix Bupleuri-Radix Paeoniae Rubra-Radix Angelicae Sinensis”in perioperative period. The couplet medicines with higher reliability include“Herba Hedyotis-Herba Taraxaci”in lump period,“Fructus Trichosanthis-Spina Gleditsiae”in abscess period,“Radix Salviae Miltiorrhizae-Radix Angelicae Sinensis”in fistula period,“Radix Angelicae Sinensis-Radix Paeoniae Rubra”,“Radix Bupleuri-Radix Paeoniae Rubra”in perioperative period；the medicine group with higher reliability include “Herba Hedyotis-Herba Taraxaci-Radix Bupleuri” in lump period,“Radix Paeoniae Rubra-Herba Taraxaci-Radix Salviae Miltiorrhizae”in abscess period,“Herba Hedyotis-Radix Salviae Miltiorrhizae-Radix Angelicae Sinensis”in fistula period,“Radix Bupleuri-Radix Paeoniae Rubra-Radix Angelicae Sinensis”in perioperative period.  Conclusion: The commonly used methods of treatment include dispersing stagnated liver qi for cooling blood and clearing heat-toxicity,Radix Bupleuri and Chinese materia medica for clearing heat and removing toxicity are essential for the treatment of this disease. The data mining explores the synergy characteristics of compound recipes in traditional Chinese medicine at the macro level,which has certain guiding significance for the prescriptions in the clinical syndrome differentiation and treatment of traditional Chinese medicine.