The utility model belongs to the technical field of transport electric installation technique and specifically relates to a plug -in power transmission line steel -pipe pole fastening device, including the grafting sleeve, be provided with the joint board on the grafting sleeve, the telescopic outer wall of pegging graft is seted up flutedly to the adjacent setting with the joint board of recess,the outer wall fixedly connected with wedge of joint board, the telescopic bottom fixed connection closing plate of pegging graft, peg graft telescopic one side and first steel pipe pole fixed connection are kept away from to the closing plate, the outer wall of first steel pipe pole has cup jointed the sleeve, the outer wall threaded connection of first steel pipe pole has fastening nut, closelylaminate with fastening nut's lateral wall in telescopic one side, telescopic opposite side contacts with the outer wall of wedge, and this plug -in power transmission line steel -pipe pole fasteningdevice is convenient and fast when the equipment steel pipe pole, has stronger bearing capacity to can prevent to take place rotatory, dislocation between the steel pipe pole, promote whole transmission line's stability.