This is related to the national economic development, artistic and cultural trends and female psychological characteristics. Every previous fashion change was accompanied by national economic growth, international war and women's equal right to work. For example, between 1920-1929, Chanel designed a little black dress and a straight dress without waist. After World War I, women began to fight for more freedom rights. Then reflected in the dress at that time, women began to wear trousers and cut their hair short, and no longer emphasized breast enhancement and waist reduction. At that time, women were qualified to get rid of the shackles of men and needed to publicize that "women should also be independent."