The theory of music imitation lacks a role in clarifying facts involved in terms of the content and expression of music. Many discussions are seemingly superficial and fail to explore the essence of the theory of music imitation. In fact, Plato pointed out that music could only refer to itself; hence, it failed to achieve imitation effects without the help of language or other representational mediums. Aristotle put forward that music essentially expresses emotion by imitating the motion of certain properties. Moreover, the theory of tone painting emerged during the 18th century and posited that people could view concepts directly through music. Although theorists frequently used them, the first two methods were independent from imitation. In reality, the theory of expression and the theory of tone painting adopted the core of imitation theory, which was seemingly the best method for solving difficulties when explaining the connection between the outside word and music, which is a non-representational medium. Poetry, music, and dance may share the same origin from the diachronic perspective. At the same time, they may be differentiated and grouped into several branches. In summary, the imitative understanding of music became a necessity, whereas the theory of tone painting resisted this status of differentiation.