The invention relates to a corn grinding device. The corn grinding device comprises a fixing box, a grinding mechanism and a driving mechanism, wherein the driving mechanism comprises a motor, a rotating rod, a connecting rod, a gearbox and a first gear, wherein the grinding mechanism comprises a grinding box, a grinding block, a second gear, a feeding pipe, a spring and a limiting block. According to the corn grinding device, grinding of the main body is achieved through cooperation of the driving mechanism and the grinding mechanism, smashing and grinding of the main body are achieved through cooperation of the grinding block and a pushing block, grinding of the main body is achieved through pushing of the pushing block, therefore a gap between the grinding block and the pushing block is reduced, and the grinding efficiency is improved; and linkage of a plurality of mechanisms is achieved through the same driving source, the use practicability is improved, meanwhile, through a movable transverse rod, collection of the main bodies is conveniently achieved, the main bodies remaining in the grinding box are reduced, and the main body grinding yield is increased.