In the west, democritus in ancient Greece had a music monograph, but it has been lost and its ideological outlook is unknown, so it can't be compared with Yue Ji. Plato and Aristotle both have ideas about music, but they are not systematic and far from being as rich and perfect as Le Ji. Although Pelodmo's On Music in ancient Rome is a monograph on music theory, its main purpose is to criticize and deny the aesthetic education theory of ancient Greek music, and it has not actively established its own musical ideological system. Therefore, it can be said that 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.
But Yue Ji regarded music as a tool in the hands of the feudal landlord class. Joy begets sorrow. I hope that through music education, "the official rank is appropriate" and "it is necessary to show that future generations also have official ranks." Yue Ji advocates that "morality is superior to art", that is, the "virtue" of the feudal landlord class is the standard of "goodness" and the political standard for evaluating music. Yue Ji believes that music embodies the "natural principle", that is, it is endowed with goodness, and "a gentleman knows joy". Music can be used to praise the virtue of a gentleman, publicize the merits of a ruler and serve to consolidate the rule. For the people, music is a gift from the rulers. The purpose of receiving music education is to make people "control their desires" and "reform", so as to "have no complaints" and "argue" and obey the rule. Therefore, Yue Ji highly praised all the music of the ruling class since the Three Emperors and Five Emperors, and praised it as "Yin Yin". Instead, he attacked all folk music and denounced it as "rape", "evil", "drowning" and "lewd music" Yue Ji overemphasized that Yue must cooperate with Li, and Yue was tightly tied to Li's car, which made Yue gradually lose its independence and creativity. Too much emphasis on the musical standards of "virtue" and "position" in Yueji tends to vulgarize and snobbery China's ancient music. The music in ancient China declined more and more, which was related to the idea that "Music" and "Rite" were coordinated. These are the class and time limitations of Yue Ji.
After Yue Ji, Ji Kang put forward the theory of "sound without sorrow and joy", holding that "sound should be based on good and evil, so there is no sorrow and joy; Sorrow should be based on emotion, not on sound. " He highlighted the artistic features of music itself, tried to make music "more famous and more natural", affirmed that "Zheng Sheng is the best voice", and challenged traditional Confucian music thoughts such as Yue Ji. Feng Menglong also believes that folk music "uses the true feelings of men and women as fake medicine for teaching", which fully affirms the "voice of righteousness" denied by Confucian traditional music thought, and their negation and breakthrough to the thought of music recording. This view was rare in China in the past.
The style of Yue Ji is broad and profound, mainly based on Confucianism and eclectic. It talks about the origin of music, its characteristics, the relationship between music and politics, its social value, the relationship between music form and content and so on. The rest of the articles only have one title, involving musical instrument performance, music creation, melody theory and other issues.