Japanese era is the foundation period of Western Music in Taiwan; however, the practices of Western Music during this period are still unexposed except those in school and church. To learn how Western Music are performed in Taiwan during Japanese era, this thesis plays main observation on the concert life. By analyzing the concert programs, sponsors and organizers, performers, audiences, and criticisms in newspapers and journals, this thesis shall study the constructing process of the sound of Western Music and its context in Taiwan Japanese era; that is, the history of how Western Music be performed, transferred, and accepted in Taiwan during Japanese era. About the soundtrack of Western Music in Taiwan Japanese era, it had been developed in three types of concert: the benefit concert, the New Park Musical Hall concert, and the Railway concert. Later it was promoted by another three types of concert: the school concert, the local organization concert, and the civilized institution concert. In 1930s, the soundtrack of Western Music became wider and more abundant due to the introductions of western record music. Despite such development didn’t go any further in war time, the practices of Western Music were still animating by dint of its social and political functions in late Japanese era. In this constructing process, the concept of Western Music was unfixed. First people learnt it from the form of Western Music instruments, but later they learnt the aesthetics of Western Music. Moreover, the music appreciation of audience was also changed. They first focused on the visual experiences, but later they started to develop the receptiveness of listening. In discuss the social value of Western Music in Modern Taiwan, such as “high class”, “art”, “progressive”, etc., they were passed on Western Music through the spectacular and intellectual aura, famous foreign musicians, and civilized properties of Western Music activities, thus made Western Music become a type of fashion music in Taiwan Japanese era.