The invention discloses a high-efficient grain impurity removing device. The high-efficient grain impurity removing device comprises a tank body, a screen cylinder assembly, a scraper assembly and a dust collection assembly. The screen cylinder assembly is arranged in the tank body and comprises an upper screen cylinder. The lower end of the upper screen cylinder communicates with a vertical straight pipe. A lower screen cylinder is fixedly connected with the lower end of the vertical straight pipe. A vertical straight cylinder is fixedly connected with the lower end of the lower screen cylinder and rotationally connected with a tank body bottom plate through a bearing. By arranging the screen cylinder assembly composed of the upper screen cylinder, the vertical straight pipe, the lower screen cylinder and the vertical straight cylinder, big and small solid particles in grain are screened out and collected and discharged through a material guide cover. By arranging an air outlet cover,a dust collection cover and the dust collection assembly composed of an air blower and a cyclone sedimentation cylinder, the air outlet cover and the dust collection cover are arranged oppositely, through the air outlet cover tangential to the tank body, air flow is in an annular shape, light garbage enters the dust collection cover along the inner wall of the tank body and then enters the cyclone sedimentation cylinder for sedimentation collection, and the light garbage removing efficiency and effect are improved.