The invention relates to a device for circularly heating and reusing old asphalt concrete, which comprises a machine frame. A drying room is arranged on the machine frame, and a heating pipe device is arranged in the drying room. A first conveying device is arranged on the upper part of the machine frame, and a second conveying device is arranged below the first conveying device. One end of the first conveying device and one end of the second conveying device are positioned outside the drying room, while the other ends are positioned inside the drying room. A feed hopper is arranged above an external end of the first conveying device, and a stirring cylinder is arranged below an external end of the second conveying device. The conveying directions of the first conveying device and the second conveying device are opposite. The first conveying device coveys from the outside to the inside, and the second conveying device coveys from the inside to the outside. A slag stopper is arranged on an inner wall of the drying room in front of inner ends of the first conveying device and the second conveying device. An oil collecting tank is arranged below the second conveying device in the drying room, and is communicated with an oil outlet formed on the drying room. The device for circularly heating and recycling the old asphalt concrete has the advantages of ingenious and reasonable structure, high efficiency of treating waste on road surfaces, complete reuse of materials, and stable quality of roads re-paved by recycled materials.