This article, influenced by the "center" concept and subversion of process philosophy to conventional ontology, proposes process metaphor, a new type of metaphor parallel to ontological metaphor and analyzes its motivation, theoretical advantages and its compatibility to TCM theories. By analysis, process metaphor is rooted in the process-featured "xiang" of TCM. it adheres to the expression method and term system adopted by ontological metaphor and it is complementary to ontological metaphor's incomplete interpretive power of TCM theories. It is distinct from verb metaphor and event structure metaphor; and is in line with related findings of linguistic typology and parabolic projection and its conceptual feature can be proved by its comparison with grammatical metaphor its validity can be inversely proved by English translations of Wuxing.