Abstract: Internal pod damage during mechanical peanut picking is a critical issue that constrains harvesting quality．Through theoretical modeling, numerical simulation, and experimental validation, a cross-scale analytical model integrating mechanics, kinematics, and energy transfer has been constructed to reveal mechanisms by which drum rotational speed and pod-picking clearance affect internal injury formation．Based on Hertzian contact theory, a quantitative relationship between impact force and relative velocity to power of 6/5 dependence has been established．A motion equation for plant in a moving coordinate system has been formulated, and material motion modes was classified through throwing index．An energy transfer model has been developed to clarify critical conditions for mechanical energy conversion into damage energy．Single-factor analysis has revealed that drum rotational speed regulated damage by altering impact intensity and collision frequency; within optimized range of 7.5 to 9.0 rad/s, picking efficiency exceeded 94% and internal injury rate was less than 8%．Picking clearance influenced damage by adjusting compressive stress; when set to 85% to 90% of pod's characteristic size（9.0 to 11.5 mm）, clean picking rate was over 96.5% with an internal injury rate below 7%．Bench tests have validated model's effectiveness, with a relative errors below 8% between simulation and experimental results at optimal parameter combination．Proposed optimization ranges were derived based on a 600 mm diameter nail-tooth drum and Huayu No.22 peanut variety（moisture content 18% to 22%）．Dynamic adjustments should be made according to machinery type, cultivar, and moisture content during practical application．