The work aims to propose a calculation model of energy rate of absorption, transfer and conversion based on the geometrical characteristics of impact contact surface to solve the problems of energy changes of packing materials at interface and their quantitative characterization during sphere oblique impact. Firstly, the geometrical characteristics of contact surface of sphere oblique impact was analyzed, and the computation formula of the absorption rate, transfer rate and energy ratios at different directions was proposed through the areas of base circle and slip surface. Subsequently, the test device of oblique impact of sphere free falling was built. Then, the effects of the impact angle, cushion thickness, drop height, sphere diameter and material density on the energy parameters were analyzed. It was feasible to calculate the energy absorption rate and conversion rate by impact contact area, following the law of conservation of energy. The energy absorption rate was nearly above 75%, becoming greater with increasing drop height, sphere diameter and material density, while the effect of impact angle was slight. The normal rate of energy conversion decreased with the increasing impact angle and the decreasing sphere diameter, but the tangential energy ratio was opposite, and the falling height and density had no obvious effect on the energy ratio. Under given working conditions, the optimum energy absorption thickness of the cushion was 4 mm. This analysis can be conducive to studying the energy change and contact characteristics at the interface of packing materials.