The utility model relates to a loose-leaf paper binder. The utility model comprises a hard cover which is assembled with the loose-leaf paper binder to form an integrative structure, and a bookbinding rack which is installed at the inner side of the side surface of the loose-leaf paper binder. The bookbinding rack comprises an installation bottom plate, a connecting shaft, a fixed paper threading rack, a movable low threading rack, a lock pressing plate and a torsion spring. The fixed paper threading rack is composed of a supporting plate (4) and a sleeve barrel (5). The lock pressing plate (7) is provided with a locking hole (8) and a hinge ring (6). The movable paper threading rack is positioned at the inner side of the lock pressing plate and is inserted in the sleeve barrel of the fixed paper threading rack, and the torsion spring is fallen into two. When the utility model is used, the loose leaf papers can be conveniently clamped or taken. The utility model is suitable for the installation of a plurality of loose leaf papers, and the taking part is also in orderly state.