In the process of using discrete element method (DEM) to simulate the interaction between straw and machinery, because the existing straw model does not have destructible characteristics, some interaction process cannot be simulated, which affects the accuracy of simulation. In order to solve the above problems, based on Hertz-Mindlin (no-slip) contact model and bonded-particle model (BPM), a mechanical model of wheat straw with destructibility was constructed. In this model, two kinds of bonding keys with different bonding parameters were used to bond the straw unit. The bonding parameters of straw model were calibrated by tension test, compression test, three-point bending test, shear test and response surface methodology. By calculating and solving the regression equation of Box-Behnken design, the bond parameters were calibrated as Bond1 (2.72×10 12 N/m 3 , 1.8×10 12 N/m 3 , 4.08×10 7 Pa, 2.54×10 7 Pa) and Bond2 (5.3×10 10 N/m 3 , 3.77×10 10 N/m 3 , 7.32×10 6 Pa, 3.79×10 6 Pa). The model can simulate the breaking, fracturing, bending and shearing behaviors of straw in the process of tension, compression, bending and shearing. The tensile strength, compressive strength, modulus of elasticity and shear strength of the model are 9.84%, 1.99%, 10.21% and 15.57% different from the experimental average values. The results show that the straw model can accurately reflect the mechanical properties of wheat straw while having destructive properties, which not only helps to improve the accuracy of straw simulation, but also provides a reference for modeling the interaction between straw and other crops and mechanical equipment
