The utility model provides a device for isoelectrically replacing an insulator and an accessory of an iron tower of a transmission line, which comprises an insulating flat ladder (2), one end of which is fixed on the iron tower and is transversely extended so that the other end is suspended at a certain distance which exceeds a work phase; an insulating swinging ladder (3), the upper end of which is movably connected with the other suspended end of the flat ladder (2), and the lower end can be downwards extended in a swinging way; an insulating rope (8), one end of which is directly or indirectly connected with the insulating swinging ladder (3) for leading the swinging ladder (3) to be swung to a work position (9) for replacing the insulator and the accessory by drawing; and an isoelectric ladder (4), the upper end of which is movably connected with the lower end of the insulating swinging ladder (3), and the lower end is perpendicularly downwards extended, and the isoelectric ladder is provided with an isoelectric seat (6) for leading workers to work with electricity. The device firstly systematically researches a method and develops a tool for replacing the insulator and the accessory of a circuit of a 110kv multi-channel small-distance perpendicularly-arranged tower with electricity.