The invention relates to the field of lamps, and provides a lamp with an overheat protection mechanism. A substrate is arranged in a shell of the lamp, and LEDs which are in electrical connection and overheat protection units are arranged on the substrate. The overheat protection units are directly attached to the substrate through heat conduction planes. Accordingly, when the LEDs operate and generate abnormal overheating, the heat energy of the LEDs can be directly conducted to the substrate, and the heat of the substrate is directly conducted to the overheat protection units through the heat conduction planes; then the overheat protection units can be directly and quickly heated to react, and the LEDs are made to stop operating. The phenomenon that the LEDs continuously operate to generate overheat loss is avoided.