The invention discloses a grain cleaning and conveying device for a rice thresher, and relates to grain harvesting devices in agricultural machines. The grain cleaning and conveying device comprises a grain collecting hopper 8 and a grain outlet barrel 6, a winnowing device composed of a winnowing barrel 2, a winnowing impeller 7 and a conveying shaft 19 is further arranged on the lower portion of the grain outlet barrel 6, and one side of the winnowing barrel 2 is communicated with one side of the grain collecting hopper 8. The conveying shaft 19 extends towards the other side along the lower portion of the grain collecting hopper 8, and spiral grain conveying blades 20 are further arranged on the conveying shaft 19. The grain cleaning and conveying device has the advantages of being capable of improving the grain output height, enabling grains to be received through bags conveniently, being capable of achieving secondary fine selection and the like, and the grain cleaning and conveying device can be used in cooperation with existing various power rice threshers with the grain conveying function, can be used for grain threshing, and can also be used for wheat threshing.