The invention provides a multi-stage exhaust gas treatment device. The exhaust gas treatment device comprises bag-type dust collectors, filter tanks, a collection box and a spray purifying tank, the bottom end of the spray purifying tank is connected with the collection box through a main pipe, two filter tanks are arranged and symmetrically located on both sides of the main pipe, the positions, close to the main pipe, of the filter tanks are communicated with the main pipe through air outlet pipes, and the positions, away from the main pipe, of the filter tanks are connected with bag-type dust collectors through air inlet pipes. According to the exhaust gas treatment device, exhaust gas is treated by adopting a multi-stage treatment manner of the bag-type dust collectors, the filter tanksand the spray purifying tank, the absorption rate of the exhaust gas can be improved, and the industrial discharge standard can be achieved; through special design of internal structures of the spraypurifying tank and ingenious combination of sprinkle heads and partition plates, the sprayed water is reflected by the partition plates, and the exhaust gas is in contact with the water repeatedly toimprove purification efficiency; through the arrangement of circulating pipelines and the collection box, the sprayed water is effectively recycled and reused, the use cost of water is reduced, and the purpose of green environmental protection is achieved.