Facing with the problem that manual cleaning for bay scallop is Labor-intensive, low efficiency，poor health conditions and the demands of industrialization and mechanization production. A kind of double-brush-roller and high-pressure gas spraying combined washing machine was designed, which was efficient and energy saving. It solved the problem that the survival rate of scallops cleaned by high-pressure water. It has been determined that on the premise of scallops cleaning effect and the efficiency, the highest cleaning degree of removing impurity could reach 3.848% and the survival rate could reach 98% under the parameter combination, that the roll core distance of the upper and lower roller brush of two adjacent rows is 111 mm, the speed v₁ of the brush rollers on both sides of the next row is 120 r/min, the speed v₂ of the brush roller under the middle row is 360 r/min, the speed v₃ of the upper brush roller is 200 r/min. It provides the reference value and a great significance in guiding production for the determination of the main parameters of the key parts which determine the scallop cleaning effect.