As an iconic American composer, Terry Riley (born 1935) is always considered as a minimalist. However, this kind of thoughts would be ignoring part of his creativity. In fact, Riley added plenty elements in his compositions since 1970s, especially when he started collaborating with the Kronos Quartet. Riley’s composing style is very extensive, including improvisation, polyrhythm and jazz. He adopted classical elements, such as instrumentation, musical forms, structure and tonality. He also combined the elements from different periods to create unique musical textures. This research focuses on Terry Riley’s String Quartet, G Song. The research will be divided into two parts. The first part introduces Riley’s life and the background of G Song. The second part focuses on music analysis, including the musical structure “Two forms in one work”; The harmony “Unresolved Dissonance”; The rhythm “Metric Modulation”; The baroque “Canon”; The modern “Pointillism”. The purpose of this study is to discuss how Riley combined classicism and modernism into a work, and discuss why the statement “Terry Riley is considered as minimalist” would be ignoring part of his story.