This invention discloses a concentric alignment method and its adjust device. The method is characterized by the following: putting two adjust devices located outside outer iron cores onto the alignment platform tracks; aligning the inner core on the left and right supportive poles; the adjust device makes the inner and outer cores with even gap in diameter; pushing the inner or outer cores for alignment. The adjust device carriers are located on the steel rack of the level moving structure and the inner core moves levelly. Through the level rollers moving of the structure and the inner core moves vertically. The adjust device guide axis drives inner iron make high position adjusting.