The invention discloses a drowning alarm, which comprises a fastening device fixed on a wrist or a finger and a dye box arranged on the fastening device. The dye box is provided with a dye in the boxbody, and a buoyancy tank capable of floating on the water surface is arranged above the dye. The shape of the buoyancy tank is matched with the shape of the inner part of the port of the box body ofthe dye box. The bottom of the buoyancy tank is connected with the bottom wall of the box body of the dye box through a plurality of elastic resetting parts, and the buoyancy tank is fixed in the dyebox by a holding mechanism. In the box body of the dye box, the outer surface of the bottom wall of the buoyancy tank is provided with a speaker, a sound integrated circuit board and an elastic guideplate arranged on the sound integrated circuit board for conducting the circuit, and the bottom of the dye box is provided with a push-and-pull sheet which is buckled with the elastic guide plate forpreventing the elastic guide plate from conducting the circuit. When a button is pressed, the catching mechanism releases the buoyancy tank, the buoyancy tank pops up, the push-pull sheet and the elastic guide plate are separated, and the elastic guide plate conducts the sound integrated circuit board to give an alarm sound. The drowning alarm achieves short distance sound and color alarming.