The invention discloses a water-cooled horn, which comprises a T-iron, a magnet ring, a voice coil, a basin frame, a water pump, a cooling cavity, a water inlet pipe, a water outlet pipe, a circulating water tank, a first hose, and a second hose. The T-iron is composed of a vertically arranged disc body and a horizontally arranged column body. The column body is fixed on the right center of the disc body. The magnet ring is sleeved on the column body. The left side of the magnet ring is fixed with the disc body. A cover iron is fixed on the right side of the ring, and the right end of the cover iron is fixed with a basin frame. The cover iron is ring-shaped, and a ring-shaped cooling cavity is provided inside the cover iron. Water inlet pipes and outlet pipes are arranged on the cover iron. The water inlet pipe is connected with the first flexible pipe, the first flexible pipe is connected with the water pump located in the circulating water tank, the water outlet pipe is connected with the second flexible pipe, and the end of the second flexible pipe extends into the circulating water tank. The present invention arranges the cooling cavity in the cover iron so that the horn can be effectively cooled, thereby ensuring the sound quality of the horn and prolonging the service life of the horn.