OBJECTIVE： To analyze the formulation regularity of Chinese patent medicine for knee osteoarthritis （KOA）， and to provide reference for the clinical standard use of Chinese patent medicine for KOA and the research and development of new drugs. METHODS： Chinese Pharmacopoeia （2015 edition， part Ⅰ），National Drug Reimbursement List （2017 edition）， National Essential Drug List （2017 edition）， Chinese Materia Medica Preparation （1992 version）， Compilation of National Standard for Chinese Patent Medicines （2002 edition）， Handbook of Rational Application of Chinese Patent Medicines in Surgery and Orthopedics （2010 edition） were searched to collect the type and formulation of Chinese patent medicines for “KOA”， “osteoarthritis”， “Bi syndrome”， “promoting blood circulation and removing blood stasis， dispelling wind and removing dampness， tonifying liver and kidney”. Supplementary the type and formulations of Chinese patent medicines for KOA by questionaire survey of clinial experts. The types， properties， meridian tropism， frequency and combination of medicinal materials used in Chinese patent medicine formulations were counted by using TCM inheritance auxiliary platform software V 2.5. The association rules and entropy clustering method were used to analyze the formulation regularity. RESULTS： A total of 190 Chinese patent medicines were collected， involving 289 TCM. With the top 10 used frequency being Angelica sinensis （75 times）， Boswellia carterii （55 times）， Carthamus tinctorius （53 times）， Commiphora myrrha （51 times）， Achyranthes bidentata （49 times）， Notopterygium incisum （47 times）， Angelica pubescens （45 times）， Saposhnikovia divaricata （45 times）， Angelica dahurica （39 times）， Ligusticum chuanxiong （39 times）. Medicinal material were mainly Xinwen in properties field and mainly liver meridian and spleen meridian in meridian entry field. Top 5 frequency of medicinal material combinations were C. myrrha-B. carterii， B. carterii-A. sinensis， A. sinensis-N. incisum， A. bidentata-A. sinensis， L. chuanxiong-A. sinensis. 14 core medicinal material combinations and 7 new developed formulations were concluded. CONCLUSIONS： This study analyzed the formulation regularity of Chinese patent medicines for KOA with the help of TCM inheritance auxiliary platform software V 2.5， which can provide reference for clinical differentiation of symptoms and signs and research and development of related new medicines related to KOA.