In order to solve the problem of the lack of intrinsic sunflower seed parameters and contact parameters between sunflower seeds and sunflower mechanized planting and harvesting equipment when simulating and analyzing the key working processes of sunflower seed sowing and harvesting using the discrete element method, 1013, SH361 and SH363 were used as the objects of this study. Based on the triaxial size and volume distribution of the sunflower seed geometric model, a discrete element model of the sunflower seed was established using a 3D scanning inversion modelling technique and the "Hertz-Mindlin (no- slip)" contact model was selected. The physical properties of the sunflower seeds were determined by physical tests and the static and rolling friction coefficients of the sunflower seeds were calibrated using the Plackett-Burman test, the steepest climb test and the Box-Behnken test. The best combinations of parameters were the coefficient of static friction and rolling friction between 1013 seeds are 0.30 and 0.03 respectively SH361 is 0.34 and 0.02 SH363 is 0.41 and 0.03. Other non-significant parameters are set to intermediate levels. The research results show that the sunflower seeds model and the calibrated discrete element simulation parameters are reliable, which can provide references for the sunflower seeds discrete element simulation research.