Objective To analyse the clinical features of diabetic peripheral neuropathy (DPN) and employ data mining technology to explore the rules of Chinese herbal medicine (CHM) therapy. Methods The clinical data of 216 patients with DPN and qi-yin deficiency syndrome were obtained, and the clinical features of the patients were assessed by cluster analysis. Relevant information was entered into the clinical diagnosis and treatment collection system, and data mining techniques were used to analyse the drug frequency, core CHM, CHM pair, and so on. Results In this study, glycated haemoglobin (HbA1c) and homocysteine (HCY) were closely related to the pathogenesis of DPN. Overall, 162 patients had typical DPN syndrome characteristics, and we analysed 216 prescriptions, including 182 CHM. The frequencies of prescription of Astragalus membranaceus, Ligusticum wallichii, Poria cocos, and Radix Rehmanniae were greater than 45%. A Bayesian network analysis diagram showed that the 9 most common core CHM included Astragalus membranaceus, Ligusticum wallichii, Poria cocos, atractylodes rhizome, and Salvia miltiorrhiza Bge. According to the association rules of CHM, Radix Ophiopogon is used for Codonopsis pilosula; Astragalus membranaceus and atractylodes rhizome for Rehmannia are also frequently used. Astragalus membranaceus and Cinnamomi Ramulus or Ligusticum wallichii and Moutan bark were highly related to a decreased Michigan Diabetic Neuropathy Score. Conclusion HbA1c and HCY are related risk factors for DPN. Numbness is a typical syndrome characteristic. Astragalus membranaceus is a monarch CHM and is used most frequently.