The name of the Chinese medicinal plant peony (Mu Dan) was discussed widely in many studies, but has not been fully substantiated to date. This paper examined the history of the tree peony in China and reviewing early relevant medical literature by drawing on the results of historical studies, early literacy works and the cultivation time of ornamental peonies. The paper found that the Chinese plant named Mu Dan was normally referred to as the Ardisia species before the early Tang Dynasty. The plant names and physical items in terms of medicinal materials were not equivalent but one-to-many in most cases. This research attempts to provide a basis for further research.