The invention discloses an automatic removing device for centrifugal fan impeller slag. A common base, a first slag removing component and a second slag removing component are included, wherein the first slag removing component and the second slag removing component are arranged on the base. The first slag removing component is provided with a bearing box arranged on the base, the bearing box is provided with a first bearing, a second bearing, a main shaft penetrating through the first bearing and the second bearing, an adjusting piece for adjusting the rotation angle of the main shaft, a fixing piece arranged on the main shaft and used for fixing a centrifugal fan impeller, a steel shoveling piece used for conducting slag removal on the centrifugal fan impeller fixed by the fixing piece,and a slag recycling box located under the centrifugal fan impeller. The automatic removing device can conduct slag removal on multiple specifications of centrifugal fan impellers, automatic slag removal is achieved, the removal efficiency and safety are greatly improved, and meanwhile labor is reduced.