”Seven-word song” is one of the major tunes in Taiwanese Opera. Besides observing its various rhythms, we should not only pay attention to the characteristic of the music, but also study how to create dramatic affects and other phenomenon from the copious mode changes. From the development of the mode character we can discuss the subject of evolution of the music. Moreover, we can study the subject of the effective of how the other kinds of drama affect Taiwanese Opera. In addition we can examine how musical instruments affects the development of song's mode. This article is based on ”Seven-word Song” to study the basic theory of the mode and the practice of the opera. The study employs both musical analysis and phenomenon discussion to present the issue.