Objective To summarize the prescription and medication rules for the treatment of diabetes mellitus by contemporary Lingnan famous Chinese medical practitioners through data mining analysis.Methods The literature on treating diabetes mellitus by contemporary Lingnan famous Chinese medical practitioners were retrieved from the databases of CNKI,Wanfang and VIP,and the collections of clinical experience and medical cases of contemporary Lingnan famous practitioners were also reviewed to screen the relevant medical records of diabetes mellitus treated by Lingnan famous practitioners.The information of Chinese medicine prescriptions for diabetes mellitus in the medical records was input to Excel to establish a database,and then the frequency analysis was performed in terms of the nature,flavors and meridian tropism,therapeutic-action classification of the Chinese herbal medicines and traditional Chinese medicine(TCM)syndrome types.Moreover,the association rule analysis and cluster analysis were carried out using IBM SPSS Modeler 18.0 and SPSS Statistics 26.0.Results A total of 62 medical records of diabetes mellitus treated by the 24 contemporary Lingnan famous Chinese medical practitioners such as DENG Tie-Tao,LIU Shi-Chang,XIONG Man-Qi,LI Sai-Mei,ZHU Zhang-Zhi,LIU Min,and FAN Guan-Ji were screened out for the analysis.And a total of 101 prescriptions involving 210 Chinese herbal medicines were included.There were 29 commonly-used Chinese medicines with a frequency being or more than 15 times,and they were Glycyrrhizae Radix et Rhizoma Praeparata cum Melle,Astragali Radix,Bupleuri Radix,Puerariae Lobatae Radix,Poria,Atractylodis Macrocephalae Rhizoma,Codonopsis Radix,Scutellariae Radix,etc.According to the therapeutic action,the Chinese medicines were mainly classified into the categories of drugs for supplementing the deficiency,drugs for clearing heat,and drugs for dispelling wind-damp.The primary syndrome types were syndrome of deficiency of both spleen and kidney and syndrome of liver stagnation and spleen deficiency,and the syndromes were usually complicated with the syndrome elements of qi deficiency,yin deficiency,yang deficiency,cold-damp,phlegm-damp,and damp-heat.The association rule analysis yielded 28 core drug combinations consisting of 2-4 herbs,and the cluster analysis yielded 5 new candidate prescriptions,which were mainly derived from the modification of classical formulas such as Xiao Chaihu Decoction,Fuzi Lizhong Decoction,Yuquan Pills plus Zengye Decoction,and Zuogui Pills.Conclusion For the treatment of diabetes mellitus,contemporary Lingnan famous Chinese medical practitioners primarily adopt the methods of invigorating spleen and warming kidney,and soothing liver,draining dampness and resolving turbidity,which has more distinctive regional characteristics of Lingnan and can provide a reference for syndrome differentiation and treatment of diabetes mellitus in the Lingnan area.