A device for double-sided processing through single shot peening includes: a shot peening system, a workpiece clamping mechanism for clamping a workpiece, and a rebound system. The workpiece is provided with a first through-hole, and the first through-hole directly faces a nozzle. The rebound system includes a reflecting surface, an open container, and a reflecting surface gripping unit. The reflecting surface includes an upper reflecting surface, a middle reflecting surface, and a lower reflecting surface. The middle reflecting surface is provided with a second through-hole. The upper reflecting surface and the lower reflecting surface are both made of flexible elastic materials and are both provided with waterproof layers. A partition plate is disposed in the open container and partitions the open container into a first cavity and a second cavity. The second cavity is provided with a filling liquid, and the partition plate is slidable in the open container.