Objective To analyze the prescription rules of Pheretima in the Dictionary of Traditional Chinese Medicine Prescriptions based on the Traditional Chinese Medicine Inheritance Support System (TCMISS), so as to provide a theoretical basis for the modern clinical application and new drug development of Pheretima. Methods The prescriptions containing Pheretima were collected from the Dictionary of Traditional Chinese Medicine Prescriptions and input into TCMISS (V2.5) to establish a database. The frequencies of compatibility medicinal materials, meridian of drug, and attending diseases were analyzed statistically. The association rules of the software and improved mutual information method were used to analyze the core drug combinations. “Bi syndrome” and “traumatic injury” with higher compatibility frequencies were selected and analyzed in respect of the prescription rules, core drug combinations, and new prescription combinations. Results A total of 281 prescriptions, 287 commonly used drugs, and 29 commonly used drug combinations (frequencies≥20) were screened. The frequencies of 4 natures of compatible drugs were mainly warm and cold (73.5% of the total frequency). The frequency of pungent was the highest in 5 flavors, followed by bitter, sweet, and salty (these 4 accounted for 95.9% of the total frequency). The meridian frequencies of the liver, spleen, heart, stomach, bladder, kidney, and lung ranked the top 7 (frequencies≥400), accounting for 91.8% of the total frequency. A total of 103 kinds of diseases were treated with prescriptions containing Pheretima, involving 18 kinds of attending diseases (frequencies≥6). The core drug combinations (support level 20%) was Aconiti Radix Cocta, Olibanum, Myrrha, Angelicae Sinensis Radix, and Moschus. The prescription rules of “Bi syndrome” and “traumatic injury” were analyzed, 15 groups of drugs were obtained for the treatment of “Bi syndrome” (confidence 1), and the core drug combinations (support level 31.8%) were Aconiti Radix Cocta, Aconiti Kusnezoffii Radix Cocta, Olibanum, Myrrha, Clematidis Radix Et Rhizoma, and Faecas Trogopterori; 20 groups of drugs were obtained for the treatment of “traumatic injury” (confidence 0.9), and the core drug combinations (support level 31.5%) were Aconiti Radix Cocta, Olibanum, Myrrha, Pyritum, Sappan Lignum, Angelicae Sinensis Radix, and Draconis Sanguis. Conclusion Pheretima in the Dictionary of Traditional Chinese Medicine Prescriptions is mostly compatible with drugs of promoting blood circulation and removing blood stasis, and dispelling wind and dampness. The prescription and medication method are clear. It can scientifically and intuitively reflect the prescription rules of Pheretima by analyzing the Pheretima prescriptions with TCMISS. The core drugs obtained by analyzing the attending diseases can reflect the basic treatment of the diseases, and it is in line with the clinical practice. The core drug combinations can also provide references for clinical application and new drug development.