OBJECTIVE：To provide referenc e for the construction and software development of knowledge base for rational use of TCM decoction pieces. METHODS ：By reviewing the literatures on rational drug use software and TCM decoction pieces in recent years ，the clinical characteristics of rational drug use of TCM decoction pieces as well as the characteristics and shortcomings of existing rational drug use software in the detection of rational drug use of TCM decoction pieces were analyzed ， and the core contents and difficulties in the construction of knowledge base of rational drug use software of TCM decoction pieces were summarized. RESULTS & CONCLUSIONS ：Clinical application of TCM decoction pieces was mainly based on “syndrome differentiation”，which reflected the unity of dialectics ，treatment，prescription selection and medication. Therefore ，the consideration of the rationality of clinical use of TCM decoction pieces could not blindly imitate the evaluation method of chemical medicine. Current rational drug use software was not based on the theoretical system of traditional Chinese medicine ，and it was not comprehensive and mature in the aspect of rational drug use review of TCM decoction pieces ，and lacks the knowledge base that could meet the requirements of rational use of TCM decoction pieces. Therefore ，it is necessary to construct a set of knowledge base which can meet the evaluation requirements of “consistency of principle ，method and prescription use ”of TCM decoction pieces under the guidance of TCM theoretical system. Its contents include that patient information collection ，construction of knowledge base related to diseases and syndromes ，selection of processed products of TCM dec oction pieces ，addition andsubtraction of clinical symptoms ，selection taboo of varieties of TCM decoction pieces ， compatibility taboo ， combined application of Chinese patent medicine or chemical medicine ， dosage of TCM decoction pieces ， total dosage and tastquantity of each prescription ， special de coction drugs ， medication methods and administration frequency ，etc. There are still some difficulties in the development of rational drug use software of TCM decoction pieces ，such as the construction of disease and syndrome related knowledge base and the difficulty in judging the rationality of clinical symptom addition and subtraction.