The Book of Music by () is the earliest work on music theory in China.

Mistake. Yue Ji is one of the works of ancient Chinese music theory, but it is not the earliest.

The reason why Yue Ji is not China's earliest work on music theory is that China's music culture has a long history, and the ancients started music activities as early as Shang Dynasty. Therefore, as early as14th century BC, the earliest music books appeared in China, such as "Wu Ding Le" and "Ode to Virtue".

By the Warring States Period, when Yue Ji appeared, China's music culture had developed for hundreds of years. During this period, many musicians and philosophers began to associate music with Yin and Yang, five elements, human nature, politics and universal philosophy, and developed a more profound music theory.

Therefore, Yue Ji has become one of the important works of China's ancient music theory. Although it is not the earliest, it can not be ignored for the development and influence of ancient music culture in China.

The earliest music books in China.

According to the research of archaeologists and musicians, the earliest music books in China should be Wu Ding Yue and Ode to Virtue, two ancient books of Shang Dynasty, which appeared around14th century BC.

With the passage of time, China's ancient music theory has also been enriched. Mei Wending's Theory of Music and Lv Qin's Music Enlightenment are both important works of music theory.