The invention relates to the technical field of agricultural machinery, and discloses an automatic cleaning device for a grain storage bin of a rice harvester. The device comprises moving devices anddriving wheels, wherein a guide wheel is arranged on the surface of each moving device, a driven wheel is arranged on the surface of each moving device, a sliding rod is fixedly connected to the surface of each moving device, a sliding device is arranged on each sliding rod, small guide wheels are arranged on the surface of each sliding device, a long rod is fixedly connected to the surface of each sliding device, and a spring is fixedly connected to the lower end of each sliding device. According to the automatic cleaning device for the grain storage bin of the rice harvester, through cooperative use of the moving devices, the guide wheels, the driven wheels, the sliding rods, the sliding devices, the small guide wheels, the long rods, the springs, brushes, the driving wheels, connectingrods, moving blocks, fixing devices, threaded pipes, clamping blocks and elastic metal sheets, close-range dead-angle-free cleaning is realized through the brushes and water sprayers, dirt residues are avoided, and the effect of cleaning the grain storage bin is achieved.