The invention relates to a dual-purpose vertical key baritone tuba, which consists of a nozzle pipe, a tuning device and a sound amplifying pipe, wherein the sound tuning device comprises first to third sub tuning pipes, a main tuning pipe and three vertical tuning press keys, wherein the first to third sub tuning pipes are mutually connected, the three vertical tuning press keys are respectively arranged on the corresponding sub tuning pipes, the first sub tuning pipe is communicated with the nozzle pipe, the third sub tuning pipe is communicated with the sound amplifying pipe through the main tuning pipe, all sub tuning pipes are mutually supported and connected, and the inner diameter of the first to third sub tuning pipes is 16mm. The dual-purpose vertical key baritone tuba adopts a method of enlarging the inner diameter of the three sub tuning pipes on the dual-purpose vertical key baritone tuba so that the tone is perfectly round and more mellow, so the playing effect can be improved, and in addition, more labor is saved. Furthermore, the integral structure of the original dual-purpose vertical key baritone tuba is not changed, only the inner diameter of each sub tuning pipe is slightly regulated, the original production process and devices can still be adopted for production, and the cost of production enterprises cannot be increased.