The invention discloses an electric power safety signboard which comprises a baseplate (1), wherein a first installation hole (2) is formed in the upper part of the baseplate (1); a first groove (3) and a second groove (4) which communicate with each other are formed successively in the upper surface of the baseplate (1) from outside to inside; the opening size of the first groove (3) is larger than the opening size of the second groove (2); slide ways (5) are disposed on upper and lower inner walls of the first groove (3); transparent plates (6) are disposed in the slide ways (5); the transparent plates (6) pass through the inner wall of one side of the first groove (3) and slide along the slideways (5); a warning slogan is placed in the second groove (4); and supporting plates (9) are connected by hinges respectively at symmetrical positions of the bottom of the baseplate (1). The signboard has the advantages that fixation manners are diversified; use is flexible; a service life is long; and the warning slogan is sprayed with a reflective coating, so that marking effects are good.