Abstract: In order to break the hard seed of Coronilla varia L., the hard seed breaking machine was designed according to the major characteristics of Coronilla varia L. seeds. With three-factor quadric orthogonal regression composite experimental design, the influences of the space between two plates, the rotational speed difference between two plates and the bottom plate rotational speed were investigated, and the regression equation was obtained. The results showed that the effects of space and rotational speed difference between two plates on experimental target were extremely significant(p<0.01), and the effect of the bottom plate rotational speed on experimental target was significant (p<0.05). The optimum process parameters were as followed: 2 mm between two plates, 74 r/min of the rotational speed difference between two plates, 128 r/min of the bottom plate rotational speed for the breaking-machine. These results can provide technical guidance for the breaking hard seed in Coronilla varia L..