The invention provides a compound impurity removing and sorting machine for crop seeds. Impurities such as leaves, bran hulls, dust and stones in the crop seeds can be removed. The compound impurity removing and sorting machine comprises a rack, a feeding hopper, discharging outlets, a filtering device and a dust removing device; the filtering device comprises a motor, a rotation shaft and drum screens, the motor is installed on the rack, the drum screens comprise a thick-net drum screen installed on the rack and a thin-net drum screen installed on the thick-net drum screen in a sleeving manner, the output end of the motor is connected with one end of the rotation shaft through a speed reducer, a pillow block bearing and a universal coupler, and one end of the rotation shaft is connected to the thick-net drum screen; and the discharging outlets comprise a coarse impurity discharging outlet, a clean grain discharging outlet and a fine impurity discharging outlet, wherein the coarse impurity discharging outlet is located at the end, far away from the feeding hopper, of the lower portion of the thick-net drum screen, the fine impurity discharging outlet is located under the thin-net drum screen, and the clean grain discharging outlet is located at the end, far away from the feeding hopper, of the lower portion of the thin-net drum screen and connected with the dust removing device.