Grain impurity discharging device for small corn harvester

The utility model relates to the technical field of corn grain impurity removal, and discloses a grain impurity removal device for a small corn harvester, which comprises a box body, a discharge hole is formed in the right end surface of the box body, a screening device is arranged in the box body, and the screening device comprises an impurity removal part; the impurity removing part comprises a motor, a concentric-square-shaped frame, a crankshaft, a first connecting rod, a second connecting rod, a first filter screen, a second filter screen, a sliding rod and a spring. According to the grain impurity removing device for the small corn harvester, by arranging the motor, the first connecting rod, the first filter screen, the second connecting rod, the second filter screen, the material guide plate, the concentric-square-shaped frame and the crankshaft, small-particle impurities are screened out through the first filter screen and moved out of the material guide plate, large-particle impurities are removed th