The invention discloses a pre-stress rebar anchoring device. Pre-stress rebar adopts finish rolling deformed steel bar, and the innovation is characterized in that the device is composed of an anchorbearing plate, a positioning nut and an anchoring nut; the middle of the anchor bearing plate is provided with a first threaded hole, the anchor bearing plate is pre-buried in the top face of a beam body of a box-shaped section bridge, the surface of the lower end of the positioning nut is provided with a first outer thread, the middle of the positioning nut is provided with a second threaded hole, and the positioning nut is in threaded connection with the first threaded hole through the first outer thread; the surface of the lower end of the anchoring nut is provided with a second outer thread, the middle of the anchoring nut is provided with a third threaded hole, and the anchoring nut is in threaded connection with the second threaded hole through the second outer thread; and the anchoring nut is in threaded connection with the finish rolling deformed steel bar through the third threaded hole. The pre-stress rebar anchoring device has the advantages that the structure of the deviceis simple and ingenious, the problem of stress loss during anchoring can be effectively solved, and the safety of the bridge structure is ensured.