The utility model provides a full copper rectangle bus -bar expansion joint, including wiring board, flexible copper conductor, set the right angle between wiring board and the flexible copper conductor to, set up the connecting plate between wiring board and flexible copper conductor. The utility model discloses simple structure, low cost facilitates engineering application. The bus -bar expansion joint had both satisfied the construction safety requirement, again the connection of facilicate corner horizontal bus with rectangular connection the between wiring board and the flexible copper conductor.