The invention discloses a suspension device for an overhead line warning board and a suspension tool for the overhead line warning board. The suspension device comprises a first clamping plate and a second clamping plate, wherein the front end of the first clamping plate and the front end of the second clamping plate are arranged to be of an open clamp structure, the middle portion of the first clamping plate is connected with the middle portion of the second clamping plate through a movable shaft, a locking spring is arranged on the movable shaft, a supporting pin is arranged in the open clamp, one end of the supporting pin is movably connected to the front end of the first clamping plate, the other end of the supporting pin is supported to the inner upper side of the middle portion of the second clamping plate, and a warning board fixing bolt is arranged at the lower end of the first clamping plate. The suspension tool comprises an insulation operation rod and a supporting plate, wherein the two ends of the supporting plate are respectively provided with a clamping plate body, the lower ends of the clamping plate bodies are fixedly connected with the clamping plates respectively, the upper ends of the clamping plate bodies are provided with opening jaws respectively, a screw hole is formed in the middle of the supporting plate, and a bolt which is connected with the screw hole in a threaded mode is arranged at the upper end of the insulating operation rod. The suspension device is simple in structure and convenient to operate and use, the operation of suspending a warning board can be implemented under any environment condition through the matching of the suspension device and the suspension tool, the safety is good, and the reliability is high.