The invention relates to dust removal equipment of a crusher, in particular to a closed circulation dust removal device of an impact crusher. The closed circulation dust removal device of the impact crusher comprises the impact crusher arranged on a base; a material inlet blocking curtain is arranged at a material inlet of the impact crusher; a material outlet of the impact crusher is provided with a material outlet hopper; a conveying belt is arranged below the material outlet hopper; an air inlet is arranged above the material inlet of the impact crusher; an air outlet is arranged at one side of the material outlet hopper; the air outlet is connected with an air suction pipeline; an outlet of the air suction pipeline is connected with a cyclone powder collector; an air inlet of the cyclone powder collector is hermetically connected with the outlet of the air suction pipeline; an air outlet of the cyclone powder collector is connected with a centrifugal fan; an air outlet of the centrifugal fan is connected with an exhaust pipeline; the other end of the exhaust pipeline communicates with the air inlet of the impact crusher; the exhaust pipeline is also connected with an air supplementing pipeline; the other end of the air supplementing pipeline communicates with the air inlet of the cyclone powder collector; and an adjusting air valve is arranged in the air supplement pipeline.