The invention discloses an LED lamp for a sound box. The LED lamp comprises an LED assembly, a horn, a casing and a power supply module. The LED assembly and the horn are assembled on the casing, and a tone leading tube is arranged on the casing. Compared with the prior art, the LED lamp is provided with the tone leading tube on the casing, so that bandwidth can be expanded, and bass can be improved; the vibration displacement of the horn can be reduced, and therefore the horn is protected. In addition, an interval is reserved between the tone leading tube and the bottom surface of the casing, therefore, heat of the power supply module can be conducted out by the tone leading tube after the casing and a base of the power supply module are assembled together, additionally, a lamp cover is in a hollowed-out shape, the tone leading tube enables an inner space (a power supply cavity) in the base to be communicated with the outside air completely, accordingly, air convention in the LED lamp for the sound box is assisted, the heat dissipation area of the casing is increased, and the heat dissipation effect is good.