To investigate composition rules of with heat-clearing Chinese patent medicine.Methods: The prescriptions of Chinese patent medicine with heat-clearing in “The new national Medicine” were collected to build a database of the methods of association rules with apriori algorithm and complex system entropy cluster were used to achieve the frequency of medicines and association rules between drugs.Results: Data-mining results indicated that in the prescriptions of Chinese patent drugs with heat-clearing,the most frequently used drugs were Radix Glycyrrhizae,Radix Scutellariae,Borneol,Flos Lonicerae Japonicae,Radix et Rhizoma Rhei,and Fructus Forsythiae.The most frequently used drug combinations were “Radix Glycyrrhizae with Radix Scutellariae”,“Radix Glycyrrhizae with Radix Platycodi”,and “Fructus Forsythiae with Flos Lonicerae Japonicae”,etc.Medicine with a high degree confidence coefficient of association rules include “Bezoar->Borneol”,“Radix Platycodi->Radix Glycyrrhizae”,“Cinnabis->borneol”,and “Fructus Gardeniae-> Radix Scutellariae”.Conclusion: In the prescriptions of Chinese patent drugs,there includes not only the drugs with heat-clearing property,but also that with resuscitation,calming,lapactic and other properties.