To address the problem of the lack of effective discrete element models in the design and simulation analysis of water caltrop dehulling primary processing equipment， this paper carries out the research work of water caltrop discrete element parameter calibration and prototype test. The 3D inverse technique was used to obtain the water caltrop profile model， and the water caltrop intrinsic parameters and basic contact parameters were measured by physical tests. The average shearing force of the water caltrop was obtained from the uniaxial compression test as 352.95 N， and this was used as the calibration target. Based on the Hertz-Mindlin with bonding model， a water caltrop discrete element model was established to carry out virtual calibration tests on bonding parameters， and the calibration range of each parameter was initially screened by single-factor tests. The two-level analysis factor test and the steepest climb test were used to quickly screen the significant factors and their calibration intervals， and the Central composite response surface test was designed to solve the bonding parameters to determine the optimal combination of parameters in the discrete element model， and a rotary shear water caltrop simulation model was established to study the effects of different tools on water caltrop shear at different rotational speeds， which was used as a basis to design a shear vibration-type water caltrop sheller to carry out prototype tests to verify the reliability of the model. The results show that，the significant effect on the shearing force of the factor normal stiffness per unit area is 4.818×10⁷ N/m³， shear stiffness per unit area is 5.343×10⁸ N/m³， the remaining insignificant factors are taken as the middle level， that is， the normal stress per unit area is 1×10⁷ Pa， shear stress per unit area is 1×10⁷ Pa， bond radius of 1.6 mm. The shearing force of the simulated test is 352 N， with an error of 0.269%； the minimum shearing force of the rectangular tool screened from the rotary shear test is 93.20 N at 230 r/min， with an error of 0.215% from the predicted value of 92.99 N； the prototype test shows that the rectangular tool has better performance than other rotational speeds in shearing water caltrop angles at 230 r/min； the comprehensive demonstration shows that the established discrete element model of water caltrop can provide a reference basis for the design of dehulling tools and the determination of key parameters for water caltrop primary machining equipment.