A warning triangle stand includes a triangular plate provided with a reflector, an LED lamp, a switch, and a power source. The reflector and the LED lamp are disposed on the front of the triangular plate. The power source is disposed inside the triangular plate. The power source is electrically connected with the LED lamp. The triangular plate includes a main plate, a left plate, a right plate, and an upper plate. The left plate and the right plate are hinged to two sides of the main plate. The upper plate is hinged to an upper end of the main plate. The switch is used to control the triangular plate to be in a folded state or an unfolded state. The triangular plate can be unfolded through the switch, which is fast and convenient. The LED lamp is used in cooperation with the reflector to provide a warning effect.