The invention relates to the technical field of petroleumextraction equipment, in particular to a cleaner with a replaceable drilling well grit catcher and desilter and a using method thereof. The cleaner comprises a base, a frame is rotatably arranged at the top end of the base, a screen frame is arranged in the frame, a collecting bucket is fixed to the frame, a plurality of cyclones are fixed uniformly toan inlet of the collecting bucket, liquid inlet pipescommunicate with liquid inlet pipelines of the cyclones, overflow pipes communicate with overflow pipelines of the cyclones, valves aremounted on the liquid inlet pipelines and bottom flow openings of the cyclones, the bottom flow openings of the cyclones extend into the collecting bucket, a cover plate for sealing a liquid inlet ofthe collecting bucket is rotatably fixedly to the upper end of the collecting bucket, a diversion opening is formed in the lower end of the collecting bucket, thediversion openingis inserted into theframe, and the outlet end of the diversion opening faces a baffle. The cleaner is simple in structure, liquidpassing through the cyclones can separate 20-150microns of solid particles, works of the grit catcher and desilter can be replaced during using, and the input cost is effectively lowered.