The suggestion of microcosmic syndrome differentiation is to meet the needs of clinical diagnosis and treatment of traditional Chinese medicine (TCM), the needs of evidence based medicine and the needs of the development of syndrome differentiation in TCM. The possibility of microcosmic syndrome differentiation might be the development of integration of traditional Chinese and Western medicine as well as modern science and technology. Microcosmic syndrome differentiation has its superiority and limitation. There are some problems in developing microcosmic syndrome differentiation, such as lack of standard for syndrome differentiation, contradiction between single microcosmic index and the entirety, non-specificity of the relationship between microcosmic indexes and syndromes, and the influence of disease on microcosmic syndrome differentiation, discrepancy between the essence study of TCM syndromes and the clinical practice. It is suggested that the concept of TCM syndrome is a certain pathological process during the onset and development of disease, composed of some subjective and objective indexes. The objective indexes include the macrocosmic and the microcosmic indexes, the entirety and the part.