Abstract: In order to improve the quality of silage，facilitate digestion and absorption of livestock，a new kind of grain crushing device for silage harvester was designed.Corn kernel fragmentation，broken section and kneading silk of corn cob and straw were realized.Field test results showed that grain crushing rate was greater than or equal to 95%，broken feed quantity was greater than or equal to 10 kgs，reliability was greater than or equal to 92%.This grain crushing device could meet requirements of high quality silage harvesting.And its promotion prospect was vast.