During the Mozart era, there was an outstanding clarinet performer Anton Stadler quite likes the sound of the clarinet lower range, so he talked with the famous woodwind instrument manufacturer Theodor Lotz co-developed a new instrument basset clarinet. Clarinet Concerto in A Maor, K622 was written for it. It is a pity that the manuscript has been lost. The current version of the score and performers have different interpretations. Therefore, I hope to choose a more reasonable interpretation based on the composition background, instrument comparison and music analysis of this song.

This thesis is divided into five chapters, the first chapter is the reasearch motivation and reasearch methods, the second chapter is Mozart's biography and the background of the Clarinet Concerto in A Major, K622, the third chapter explores the history and evolution of Basset Clarinet, the fourth chapter select a more reasonable interpretation of Bärenreiter's score text based on composition music structure, tonal changes, harmony structure and material analysis, and the fifth chapter will be the conclusion.