Abstract: The discrete element simulation technology can simulate wheat milling process, reduce the number of experiments, and reduce experiment cost. The discrete element simulation technology has been widely used in the agricultural field. However, there are still gaps in the mechanical parameters and contact parameters in wheat milling. In order to study the working characteristics of the roller mill IB during milling, and to simulate and analyze the milling process, it is necessary to calibrate the contact parameters and mechanical parameters between the wheat grains and the grinding rollers. According to the ASAE S368.4 DEC2000 (R2017) standard, the mechanical parameters of wheat grains after moistening were calibrated by texture analyzer, and the Poisson's ratio, elastic modulus and shear modulus of wheat grains during milling were obtained. The contact parameters of the wheat and the grinding roll were measured using the grinding roll material. The roller-wheat static friction coefficient was calibrated by the inclined plane method, and the wheat particles collided with the grinding roller material in free fall, and the collision recovery coefficient between the wheat particles and the grinding roller material was determined. The angle of repose of the wheat particles in contact with the grinding roller material was measured by the cylinder lift method. For the parameters that are not easy to measure, EDEM was used to perform virtual calibration. Taking the angle of repose as the response value, the significant influencing factors of the experiment were screened out by the Plackett-Burman test, and the ranking of the significant factors affecting the angle of repose of wheat grain accumulation was obtained. The steepest climbing test was designed to determine the value range of the optimal parameters. According to the results of the Plackett-Burman test and the steepest climbing test, a Box-Behnken test was designed to obtain the second-order regression model of the contact parameters and the angle of repose between the wheat grain and the grinding roller material. Taking the actual angle of repose as the target of the response surface, the optimal parameters were obtained according to the regression equation, response surface and contour diagram, and the optimal parameters were substituted into the EDEM for discrete element simulation test verification. The relative error rate between the angle of repose and the actual value was 1.12%. The reliability of parameter calibration is proved by error analysis, and the results of parameter calibration can be used to set simulation parameters in the process of wheat IB milling.