The utility model discloses a device for rotationally spraying polyurea on the outer surface of a long flexible inhaul cable of a bridge. Wherein the spraying device system is composed of a polyurea component A raw material storage barrel, a polyurea component B raw material storage barrel, a polyurea spraying main machine, a rotating mechanism base, a polyurea conveying pipeline, a spray gun frame, a polyurea spray gun and an inhaul cable, and a forward and reverse rotating mechanism and a pipeline winding disc are installed above the rotating mechanism base; the spray gun frame is installedon the pipeline winding disc, the pipeline winding disc is installed on the forward and reverse rotation mechanism, the polyurea conveying pipeline is wound on the pipeline winding disc, the polyureaspray gun and the forward and reverse rotation mechanism are concentric in rotation center, and the axis of the inhaul cable and the rotation center of the polyurea spray gun are concentric. By the adoption of the device and the method for spraying the outer surface of the inhaul cable through forward and reverse rotation of the spray gun and direct movement of the inhaul cable body, the problemsthat the flexible inhaul cable is too long and inconvenient to rotate, and a conveying pipeline is wound due to the fact that only the spray gun can be adopted for rotation are solved, and the automatic spraying process for spraying the outer surface of the long flexible cable is achieved.