Yue Ji is the earliest and relatively complete musical theory work in China, which summarizes the Confucian musical aesthetic thought in the pre-Qin period. Every voice is from the heart. When the heart moves, everything does its best. Emotion is moved by things, so it is shaped by sound; The sound is corresponding, so it changes; Turn into a square, that is, sound; Compared with the sound, it is fun, and drying feathers is also fun.

Yue Ji occupies an extremely important position not only in China, but also in the history of ancient music thought and music education thought in the world.