A BLUETOOTH speaker includes a cylindrical shell, a limit ring, a flow guiding mesh plate, a loudspeaker mesh cover, and a flexible sealing rubber ring. The limit ring is arranged on an outer side surface of an upper end of the cylindrical shell. The flow guiding mesh plate is arranged on a bottom portion of the cylindrical shell. The loudspeaker mesh cover is arranged on an upper end of the cylindrical shell. The flexible sealing rubber ring is arranged between the loudspeaker mesh cover and the limit ring. A printed circuit board (PCB) is arranged inside the cylindrical shell. A loudspeaker module is arranged on the PCB. A rechargeable lithium battery is arranged below the PCB. Air guiding grooves are symmetrically arranged on a lower side of the flexible sealing rubber ring.