Abstract: The paper aimed at the problem that traditional buckwheat shucker matched with the upper end of suction air flow separator, which air flow and materiel mixing asymmetrically, buckwheat shell and shelled buckwheat were not completely separated. In order to improve the separation rate and reduce the loss rate during the buckwheat shell, on the basis of measuring mixed materials suspend speed, the air-suction separator was improved and optimized experiment on suction air flow speed, the number of uniform plate and the position of aeration screen was carried out.The better level combination of main technological parameters was educed, that was suction air flow speed 8.0 m/s and aeration screen placement in middle place, three uniform plates. The results showed that the separation rate of air-suction separator was reached up to 99.3%, the rate of loss was reduced to 0.35% after optimized improvement experiments. It proved that it is effective to improve the traditional buckwheat shucker, develop the separation rate and reduce the loss rate .