The invention discloses a loudspeaker box, which comprises an upper cover, a lower cover fixed on the upper cover and forming an accommodation space together, and a sounding unit accommodated in the accommodation space. The sounding unit and the upper cover form a front cavity by enclosing, and the sounding unit, the lower cover and the upper cover form a rear cavity by enclosing; Wherein the loudspeaker box further comprises a cover plate fixed on the side of the upper cover far away from the lower cover and an air permeable separator, wherein the cover plate and the upper cover are spaced apart to form an auxiliary sound cavity, and the auxiliary sound cavity is filled with sound-absorbing particles; The upper cover is provided with a through hole penetrating the upper cover, and the through hole communicates the rear cavity with the auxiliary sound cavity. The air permeable separator is fixed on the upper cover and completely covers the through hole, and the air permeable separatorcloses the sound-absorbing particles in the auxiliary sound cavity. Compared with the prior art, the loudspeaker box of the present invention can increase the volume of the second rear cavity for being filled the sound-absorbing particles, improve the audio performance and improve the acoustic performance.