The invention relates to a button-shaped accordion conversion key terminal limiting device, comprising a bracket (1) and a limiting mechanism (2), the bracket (1) being installed on the sound board (3) of the accordion, and the limiting mechanism (2) There are two covers, and every set of limit mechanism (2) comprises a voice-changing movable sheet (21), an upper pull-out rod (22), a roller shaft (23), a lower pull-out rod (24), a sound-changing valve plate (25), a limiter Bit frame (26), fork (27), spring (28) and fork seat (29), one end of the phonation movable piece is connected with the phonation key of the accordion, and the other end is hinged with one end of the upper puller, and the upper puller The other end is fixedly connected with the roller, and the roller is installed on the two supports. One end of the lower lever is fixed with the roller (23), the other end is hinged with the end of the sound changing valve plate (25), and one end of the limit frame (26) is connected with the The roller (23) is fixed, the other end is hinged with the fork, the fork is hinged with the fork seat (29), the fork seat (29) is installed on the soundboard (3), and the spring (28) is sleeved on the fork ( 27) on. After the device is added, every time a tone-changing key is pressed, the best position can be accurately reached, so that the player can avoid problems such as channeling and automatic sound-changing when using it.