The utility model provides an emergency lamp bulb. The emergency lamp bulb comprises a housing, wherein the front end of the housing is provided with a light-transmittable shade; an LED (light emitting diode) light source is formed in the light-transmittable shade; the rear end of the housing is provided with a threaded plug; a storage battery and a control circuit board are arranged in the housing; an alternating-direct current transforming module and a control switch which is exposed outside the housing are arranged on the control circuit board; the control circuit board is electrically connected with the threaded plug, the LED light source and the storage battery, respectively; a hanging component is further formed on the housing; the alternating-direct current transforming module is used for transforming external alternating current into low-voltage direct current, so as to supply power to the LED light source or charge the storage battery. The emergency lamp bulb has the following beneficial effects: as the storage battery is embedded in the bulb, the bulb can be used emergently in power failure; furthermore, the lamp bulb is provided with the hanging component, so that the bulb can be released and separated from a lamp holder and hung in other situations for use.