The logical and realistic possibility of integrated traditional Chinese and western medicine was analyzed by philosophical principles. It is view that the fundamental reason for different theory system is due to differences in the standard and way of division of the world. A theoretical system formally accepted is usually marked by establishment of its own ontology language system. This paper adopted the intuitive concept of set to interpret the logical possibility of integrated traditional Chinese and western medicine, and found that it is realistically impossible to produce the ontology language system belonging to integrated traditional Chinese and western medicine. The identity of integrated traditional Chinese and western medicine at last depends on what kind of standard of measure we used. Based on the above theoretical review,we also analyzed the major factors influencing the future development of traditional Chinese medicine,integrated traditional Chinese and western medicine.