In order to research threshing seed-corn identity and damage mechanism, improve threshing principle, reduce damage and enhance efficiency, the threshing experiments for Longdi401 seed-corn were carried out by using the LDS microcomputer control and electron draw press test machine, to investigate the effects of variety , moisture condition, force position and restriction property. The results show that under the same condition, it's easiest at corn bottom fringe to thresh, the second is at top fringe and the last is middle fringe; the longitudinal bending force is the optimal forcing method for threshing. 