Great changes have taken place in Europe and even the world in the 20th century. At the beginning of the century, World War I broke out. From 1929 to 1933, serious economic crises broke out in European and American countries, triggering strong social unrest. Then some European countries were ravaged by the Nazis, and in the middle of the century, World War II broke out. The two world wars brought huge disasters to the people of the world, and the world's political landscape underwent fundamental changes. All of these are bound to have a profound impact on people's thoughts and psychology, and will also be reflected in music creation.

In the field of science and technology, the 20th century was a period of rapid development. For example, at the beginning of the century, Freud explored the issue of the unconscious and developed psychoanalysis; the theory of relativity proposed by Einstein triggered the revolution in understanding the universe. Technological progress is directly related to music through the invention and popularization of phonograph, radio, television and other technologies, which enabled music creation to win a wider audience. People can hear first-class performances and musical works from hundreds of years ago without leaving home.

All of this has had a profound impact on music creation. As a result, music in the 20th century, like other literature and art, has shown a trend of diversified development, that is, there are many genres, rapid changes, and many genres. The relationship between them is very complicated: there are contradictions and conflicts, but also intersections, overlaps, influences and absorptions. Even when introducing specific composers, it is difficult to make a rigid division or classification of their genres.