The present invention discloses a filtration medium ash cleaning apparatus and a high temperature gas filtration and dust removal system. The filtration medium ash cleaning apparatus comprises an ash cleaning apparatus housing (31) capable of holding a washing liquid and a conveying assembly arranged in the ash cleaning apparatus housing (31), wherein the ash cleaning apparatus housing (31) is provided with a filtration medium inlet (32) and a filtration medium outlet (33), the upper end and the lower end of the conveying assembly are respectively positioned above a washing liquid level (34) and below the washing liquid level (34) so as to convey the washed filtration medium fall into the washing liquid to the filtration medium outlet (33), a barrier plate capable of separating the washing liquid level (34) into two parts is arranged in the ash cleaning apparatus housing (31), and the upper end and the lower end of the conveying assembly are respectively positioned on both sides of the barrier plate. With the filtration medium ash cleaning apparatus of the present invention, the dust carried by the filtration medium discharged by the granule layer filter can be cleaned so as to ensure the filtration performance of the granule layer filter.