This paper studies the system and development of the yuebu, an official court music system during the Tang dynasty. Research on the music of the Tang dynasty has been quite abundant, mostly on the yanyue (court banquet music that was administered by the yuebu), with notable studies by scholars such as Ren Bantang (1982), Kishibe Shigeo (1973), Wang Xiaodun (1995), and Shen Dong (2000). However, previous research on music of the Tang dynasty emphasised acculturation and assimilation between China and cultures from bordering western countries; they did not look at music of the Tang court from the perspective of the yuebu as a complex bureaucratic system. Our interest focuses on yuebu as a functioning system that reflected a historically important route of transmission of traditional Chinese music. Through examining the cultural integration of several dynasties encompassing a period lasting more than three hundred years from the Han to the early Tang dynasties, as well as migration and training of the musicians of the yuebu and their method of musical transmission (particularly transmission within the family unit), this paper aims to gain an insight into the historical basis and cultural meaning of the yuebu. The discussion consists of two parts. Part one introduces the classification and the nature of the yuebu. On the one hand, as an official musical organisation in the court, the music repertory of the yuebu was the result of combinations of a variety of musical cultures from the Han to the Tang dynasties. On the other hand, as a bureaucratic organisation, yuebu represented a system consisting of “yue (music), qi (instruments), gong (musicians), and yi (uniform)”, legally sanctioned under the “yuelin (law on music)”. Part two concerns itself with the development of the yuebu in the Tang dynasty through scrutinizing the impact of migration and the training of musicians, and musical transmission during the pre-Tang era (namely, the Wei, Jin, Southern and Northern, and Sui dynasties). From this, the paper ventures to explore, with a musicological approach, the typical means of propagating music traditions in China via training and transmission within a relatively closed system that was self-protecting and maintained within the family unit.