This study was aimed to analyze the regulation of syndrome-treatment pattern of classical Chinese medici-nal formulae for emotional diseases based on formal concept analysis. First, we dealt with the decision formal context of 51 prescriptions about emotional symptom in the Treatise on Febrile and Miscellaneous Diseases and the Es-sentials from the Golden Cabinet based on the principle of optimization. Then, we generated a new partial-order at-tribute diagram in order to present the specific character. Finally, we explained properties of partial-order structure graph from traditional Chinese medicine (TCM) experts' point of view based on knowledge discovery. The results indi-cated the relationship between prescription and syndrome of emotional diseases. It was concluded that method pro-posed in this paper worked well in treatment of description of syndrome differentiation and discovery of new knowl-edge from the known data in the clinical diagnosis.