A screw type light-emitting device comprises a hollow mounting holder; a screw holder disposed over the mounting holder and threadedly connected with the same; a battery case disposed in the mounting holder and relatively fixed with the same; a battery pack removably disposed in the battery case 30; an LED light disposed at one end of the battery case and extending out of the mounting holder, wherein one of the electrodes of the LED light is electrically connected to the battery pack, and the other electrode extends to between the battery pack and the screw holder; both the LED light and the battery pack are mounted in the battery case, the battery case is mounted in the mounting holder, and the mounting holder is threadedly connected with the screw holder, and the LED light will emit light when the screw holder is rotated into a proper position.