The invention discloses a deburring device for the inner wall of a C-shaped guide rail, which comprises a bottom plate, a side plate, a top plate and an operation platform. Both ends of the upper end surface of the operation platform are provided with clamping devices for fixing the two ends of the guide rail. A rack and a mounting frame are arranged, and a horizontal shaft is installed on the mounting frame, and a driving gear is arranged on the horizontal shaft. And the driving gear is meshed with the rack, the lower end surface of the rack is connected with the upper surface of the top plate through a sliding mechanism, the bottom end of the rack is provided with a vertical bar, and the bottom end of the vertical bar is provided with a guide cylinder perpendicular to it, and the guide cylinder Both ends are provided with connecting rods, the opposite ends of the two connecting rods are provided with mounting plates, the mounting plates are provided with friction plates, the bottom end of the rack is also provided with a suspension rod, and the lower end of the suspension rod is provided with a vacuum cleaner. The invention has a simple structure, can be repeatedly deburred and polished, has a good grinding effect, does not need manual grinding, has high grinding efficiency, can process debris after grinding in time, is simple to operate, and has strong practicability.