In order to minimize the kernel damage, a design method of seed corn sheller with broad board-teeth, a shelling cylinder with lower rotary speed and grid concave boards was proposed in this paper. The sheller threshing kernels by extruding & rubbing, which is capable of processing both common corn and seed corn. The advantages of the apparatus are a higher threshing performance and a lower percentage of kernel damage. The equipment was adapted to shell corn ears with different moisture content from 13% to 20%. A new gentle shelling technique was adopted in this sheller, which is different from the traditional shelling principle. The shelling of the corn accomplished by the action of corn on corn and corn on cobs in a round bar cage. Some equipment was manufactured according to this technique, and the results of testing of sample sheller showed that the sheller was completely suitable for the threshing of seed corns. Some rules obtained from the design of the corn sheller were also introduced.