In this paper, I have researched the aesthetics of musical time (Zeitlichkeit). Music is the art of time, and musical time represents unique style and aesthetics. However, music radically changed in 20th century. Therefore, musical time changed, as well. The Aesthetic Meanings of musical time after the late 20th century are the main subjects of this study. Through the study, I have found four changes from traditional time; firstly, the change from linear time to circle time in the pluralistic style. Secondly, the change from deterministic time to open time in the music of chance. Thirdly, the change from teleological time to stationary time in minimal music. And finally, the change from real time to Bergson’s time concept of ‘the stream of consciousness’ in the opera of Unsuk Chin. So to speak, since 20th century, musical time has been consistently deconstructed and again reconstructed into a new category. The change of music indicates a change of time, and it can interact with a whole philosophy and art, as well as the change of society and science.