The utility model provides a warning board, including folding warning board, bind strip, spring, snap -fastener, buckle, snap ring, shell fragment and buckle, speak for warning label or warn the picture in folding warning board's front, the back of folding warning board is equipped with bellied border, folding warning board is box body of the fashionable formation of fold -over clasp backward, the back at folding warning board still is fixed with the spring, and the snap -fastener is installed to the free end of spring, and the both ends of binding the strip also are fixed with the snap -fastener, and snap -fastener and the snap -fastener on the spring binded on the strip are mutually supported, side -mounting at folding warning board has buckle, snap ring and shell fragment to detain, and when folding warning board expanded, buckle and snap ring cooperation were connected, and when folding warning board was folding, buckle and shell fragment were detained the cooperation and is connected. The beneficial effects of the utility model are that: an efficiency that warning board can bind on the structure roof beam of different thicknesses, different shapes, structure post, can use on multiple equipment, and it dismantles conveniently, and convenient to carry can improve electric operation.