The present disclosure provides a bracket connecting structure. The bracket connecting structure includes a bracket mounting piece, a mounting tube connected with the bracket mounting piece, and a locking assembly arranged on the mounting tube. The locking assembly includes a locking piece, a driving piece and a driving fitting piece which are arranged in the mounting tube. The locking piece is arranged in the mounting tube in rotating connection with the mounting tube. The driving fitting piece is rotatably connected with the locking piece. The driving piece runs through the mounting tube and is adaptively connected with the driving fitting piece.