The transposition of modern horns is one of the necessary abilities of every professional horn player. In this paper, by sorting out the development history of the horn in different periods, combined with the analysis of the structure and pronunciation principle of the horn instrument, this paper makes a more detailed discussion on the formation process and causes of the modern horn transposition performance. As a horn player, while strengthening his playing ability, he should have a deep understanding of the rich historical and cultural connotations contained in the instrument itself.