Abstract: Because of the much bigger beaten force, the paddy seeds were often broken or even interiorly damaged，and its germination rate or integral rice rate was reduced by the method of traditional rigidity thresher. In order to reduce the damages of the paddy seeds, a flexible threshing roller in parallelism of principle with rigidity pole-teeth roller was designed. Based on the study and analysis of the beating threshing processing and its principle of reducing beating forces，according to the threshing dynamics analysis, it could increase the contacting time and reduce impacting force when the flexible threshing teeth was used at a stable-roller speed; the beating force of the flexible teeth was less than that of the rigidty pole-teeth. Contrastive studies on threshing by using rigidity pole-teeth and flexible pole-teeth were made. The conclusion indicated that it could be used for threshing paddy rice when its diameter was less than that of the rigidty pole-teeth, and the indexes of threshing such as the unthreshed rate, purity, threshed rate and fringle-broken rate were similar with those of the rigidity pole teeth, and broken rate of grain threshing was prominent less than that of the rigidity pole-teeth.