Following the previous research on analogous formulae,this paper analyzes the difficulties to automatically discover the analogous formulae derivation relationship (AFDR) based on the review of current formulae similarity models.Furthermore,the paper carries on thorough analysis on connotation of AFDR and suggests it should comprise of many features and factors such as transformation,time of prescription,drug compositions and similarity.At last,on the basis of the formal representations for such concepts as Chinese materia medica and formulae as well as their relations,formal representation for AFDR is completed,which lays a stable foundation for the further research on AFDR classification model.