The invention discloses an extensible lamp. The extensible lamp comprises a lamp cap, a lamp holder, a lampshade end cover and LED lamp beads, wherein the lamp cap and the lampshade end cover are arranged at the upper end and the lower end of the lamp holder respectively; one or more lampshade barrels are further arranged between the lamp holder and the lampshade end cover, the plurality of lampshade barrels are stacked in the vertical direction, every two adjacent lampshade barrels are detachably and rotationally connected, the lampshade barrel at the uppermost end and the lamp holder are detachably and rotationally connected, the lampshade barrel at the lowermost end and the lampshade end cover are detachably and rotationally connected, a heat dissipation part is arranged in each lampshade barrel, and the LED lamp beads are arranged on the heat dissipation part in the lampshade barrel at the lowermost end; and a ventilation channel in the front-rear direction is formed in the middle of each heat dissipation part, a fan is arranged in the lamp holder, the lamp holder is provided with air inlets, the lampshade end cover is provided with air outlets, and the air inlets communicate with the air outlets through the ventilation channels. The extensible lamp can be disassembled, assembled and stocked up conveniently, and the cost of dealers is saved.