The invention relates to the technical field of early warning equipment, and discloses a fast-mounting construction anti-external damage early warning assembly, which comprises a construction anti-external damage early warning hanging device and a mounting bracket. The construction anti-external damage early warning hanging device comprises a shell, a left upright rod, a right upright rod, a left torsion spring, a right torsion spring, a distance sensing alarming assembly, an illumination sensing alarming assembly and a power supply module, wherein the left upright rod and the right upright rod are respectively fixed at the left side and the right side of the top surface of the shell. The construction anti-external damage early warning hanging device can be hung on a wire of an overhead line via the left torsion spring and the right torsion spring with the help of the mounting bracket in a fast and labor saving mode, the construction work can be alerted via the distance sensing alarming assembly and the illumination sensing alarming assembly, the construction person can accurately master the safe distance for construction, timely alerting is carried out in the case of negligence, safety awareness is enhanced, happening of external damage accidents can be effectively avoided, the structure is simple, the operation is convenient, reliability is high, and promotion is easy.