For reducing mechanical damage of corn seed in the process of threshing and mastering the law on anti-pressing properties and crack formation of corn seed, static compresses experiment of various varieties corn seeds were carried out on LDS microcomputer control and electron draw-press test-machine. Results showed that the largest breaking power would decrease with the increasing of seed humidity ratio. The largest breaking power was the biggest with levelplacing manner and in turn flankplacing manner took second place，perpendicular-placing manner was the smallest. Anti-pressing competence of various varieties corn seeds was different under same placing manners. The shape, position and law of crack in various surface loaded was different under different placing manners. 