Filter device of air compressor

A filtering device of an air compressor comprises a filtering box, a first-stage filtering mechanism and a second-stage filtering mechanism, wherein the first-stage filtering mechanism and the second-stage filtering mechanism are arranged in the filtering box. An air inlet and an air outlet used for being connected with an air compressor are formed in the filter box, and air enters the air compressor after sequentially passing through the air inlet, the first-stage filter mechanism, the second-stage filter mechanism and the air outlet; the primary filtering mechanism comprises a barrel-shaped adsorption net with two open ends and an adsorption cavity defined by the barrel-shaped adsorption net, the barrel-shaped adsorption net is detachably connected with the filtering box, one end of the barrel-shaped adsorption net is communicated with the air inlet, the other end of the barrel-shaped adsorption net is communicated with the secondary filtering mechanism, and an adjusting assembly capable of adjusting airflo