Abstract: Numerical simulation research on the interaction between broad bean and harvesting machine is carried out by discrete element method（DEM）, to realize the design and optimization of relevant parameters of key components of broad bean harvesting machine, improve research efficiency and reduce research cost. Before this, it is necessary to determine broad bean discrete element simulation parameters. In this paper, the basic physical parameters, contact mechanical parameters and angle of repose of broad bean are measured through physical tests, and the value range of simulation test parameters is selected with reference to the measurement results of physical tests, and the simulation test angle of repose is used as the response value. The test parameters with significant influence of angle（broad bean-broad bean static friction factor, broad bean-steel plate static friction factor, broad bean-steel plate rolling friction factor）; on the basis of the Plackette-Burman test, the value range of the significant parameters was determined by the steepest climbing test; the Box-Behnken test establishes the second-order regression model between the angle of repose and the significant parameters. Taking the angle of repose as the target value measured by the physical test, the significant parameters are optimized to obtain the optimal parameter combination: broad bean-broad bean static friction factor 0.25, broad bean-steel plate The static friction factor is 0.47, and the rolling friction factor of broad bean-steel plate is 0.35. Finally, P＞0.05 was obtained by T test, which indicated that there was no significant difference between the simulated angle of repose of the optimal parameter combination and the actual angle of repose, which verified the reliability of the optimal parameter combination. The research results show that the discrete element simulation parameters of broad bean calibrated by the above experiments can provide a reference for the optimal design and discrete element simulation research of broad bean harvesting machines.