The invention relates to an electric drill bit with the positioning function and for building. According to the electric drill bit, a plurality of positioning grooves are formed in the end part of a drill bit body; each positioning groove comprises a first groove region, a second groove region and a third groove region which are formed in the axial direction of the drill bit body; a positioning hole is formed in the position, at the end part of the drill bit body, of each first groove region; positioning rods are arranged in the first groove regions; each positioning rod is provided with a positioning head; the radius of the end part of each positioning head is smaller than 1 mm; a plurality of balls are arranged in the positioning grooves and roll between the third groove regions and thesecond groove regions; sliding grooves allowing the positioning rods to slide therein are formed by the third groove regions and the first groove regions; and the positioning rods can enter the thirdgroove regions so as to enable the positioning heads to be hidden in the drill bit body, or the positioning rods leave the third groove regions so as to enable the positioning heads to extend out of the drill bit body. The electric drill bit has the advantages that by means of a mode that the positioning rods extend out of the positioning grooves, the stress area is decreased, the friction force is increased for positioning so as to carry out drilling, and in the drilling process, the balls move to the second groove regions and cause the positioning rods to retract so as to realize drilling.