The invention discloses an ash removing device of an SCR denitration catalyst, which is used for cleaning ash blocks in a channel of a regenerated catalyst module. The ash removing device is provided with an ash block crusher which is used for crushing ash blocks, a crusher guide rail connected with the ash block crusher, and a negative pressure dust collector used for collecting crushed ash blocks, wherein the ash block crusher moves freely downwards along the guide rail of the crusher, so that the ash blocks in the channel can be crushed completely, and the purpose of thoroughly removing the ash blocks can be achieved.