Abstract： Objective： To study the administration rule of Professor ZHANG Hongyi treating cough by animal medicines. Methods：The outpatient prescriptions for cough given by Professor ZHANG Hongyi from January 2003 to July 2006 were selected and sorted out， and the database containing animal medicines and prescriptions was then constructed. Data mining technology was used to explore the formulation rule of prescriptions， especially the application rule of animal medicines. Results： A total of 370 prescriptions were included for statistical analysis. The result of frequency statistics showed that 58 kinds of Chinese medicines were used for over 50 times； the result of association rule analysis showed that a total of 147 rules of high- frequency drug pairs were obtained， and the association rules of drug pairs and drug groups related to Pheretima， Saigae Tataricae Cornu， Ostreae Concha and Haliotidis Concha were visualized； cluster analysis was used to generate a dendrogram， and 16 Chinese medicine groups with homogeneity were extracted；18 common factors were finally obtained by factor analysis. Conclusion：The animal medicines with high-frequency use have the effect of relieving cough and calming panting by taking the liver meridian，pacifying the liver wood，and entering the collateral vessels and dispelling wind.