In this paper, a mobile robot is assumed to be equipped with a sonar and is capable of locating the acoustic reflectors. The acoustic landmarks are chosen from the acoustic reflectors whose positions are independent of the mobile robot position. By matching the two dimensional patterns of the acoustic landmarks and the acoustic reflectors that are newly recognized, the current mobile robot position is determined. A path is constructed by adding up the acoustic landmarks along which a mobile robot can navigate without error accumulation. Experiments were performed to verify the proposed method.