The utility model discloses a high-power emergency illumination device for vehicle-mounted construction, which is installed on an engineering vehicle, wherein the engineering vehicle comprises an automotive power generator, and a storage battery connected with the automotive power generator. The emergency illumination device comprises a power converter and a metal halogen lamp, wherein the power converter comprises a direct-current 24 V input interface, a DC/AC (direct-current/alternating-current) inverter and an alternating-current 220 V output interface; the output end of the direct-current 24 V input interface is connected with the input end of the DC/AC inverter; the output end of the DC/AC inverter is connected with the input end of the alternating-current 220 V output interface; the input end of the direct-current 24 V input interface is connected with the storage battery in parallel; and the metal halogen lamp is connected with the output end of the alternating-current 220 V output interface. The emergency illumination device disclosed by the utility model has the advantages of being simple in structure, low in cost, convenient to carry, convenient and fast to connect wires, maintenance-free, convenient to use, and the like; simultaneously, the illumination height is greatly increased.