To present a data processing method of traditional Chinese medicine based on Apriori algorithm to improve the efficiency of data mining and ensure the accuracy of the knowledge or conclusion in the data mining. The importance of data preprocessing in data mining was analyzed, along with the characteristics of TCM data and the requirements of Apriori algorithm for mining data. Some new functions were formed with considerations on the exam-ples. The data preprocessing was explored from the aspects of terminology standardization, eliminating unqualified data, structured prescription data, data sorting and etc. The new functions were simple and easy to operate, and the preprocessed data made the efficiency of TCM data mining enhanced greatly. The preprocessing method based on Apriori algorithm for TCM data facilities the TCM data mining.