Abstract: Grain crushing technology is the key technology to improve the quality of silage corn feed, and it is also the bottleneck of restricting silage corn feed mechanization devices. In this paper, SW three-dimensional modeling, discrete element method, and field experiment were combined to explore the whole plant corn discrete element model, to simulate the process of crushing roller and corn straw, corn grain mutual operation in the process of grain crushing operation. The mechanical analysis of the crushing roller was carried out, and the whole plant corn adhesive contact model was used to simulate the crushing process between the rollers. Finally, the field experiment was carried out to verify the authenticity of the simulation results. In order to improve the efficiency of the crushing device and further optimize its structure, the effects of different working parameters on the operation quality and crushing rate of silage corn grain crushing device were studied. The results showed that: in the compression and shear test of corn straw, corncob, and grain, when the loading speed was 4 mm/min, and the roller gap was 2 mm, the maximum critical rupture loads of corn stalks and corn cobs under axial compression were approximately 2 360 N, corn kernel was approximately 48 N, the maximum radial critical shear forces of corn stalks and corn cobs were 625 N and 840 N, respectively, corn kernel was 23 N, and the crushing rate reached a maximum of 96%. The simulation results are consistent with the experimental results, which shows that the three-dimensional discrete element model established in this paper can be applied. It is used to simulate the crushing process of silage corn grain crushing device, and the test results meet the quality requirements of corn grain crushing, which provides a theoretical basis and technical support for further study of grain crushing mechanism and analysis of influencing factors of grain crushing.