A loudspeaker includes a housing, a conducting sound element, a rotating element, and a modulating element slidably mounted to the rotating element. The housing defines an insertion chamber and a notch. The conducting sound element is mounted in a front of the insertion chamber. The rotating element is rotatablely mounted in a rear of the insertion chamber. A rear end of the rotating element defines a holding groove. A portion of the rear surface of the rotating element is recessed forward to form a sliding groove. A front surface of the modulating element is equipped with an audio plug and defines a sliding element slidably located in the sliding groove. The audio plug is capable of being inserted into the holding groove or projecting out of the holding groove and the notch under a rotation of the modulating element together with the rotating element with respect to the housing.