Abstract: Abstract: This study investigates the dynamic response characteristics of silica sand under dynamic loading using the modified Split Hopkinson pressure bar (SHPB) to understand its crushing characteristics and energy-absorbing effects. Four different grain groups were examined, and the results demonstrate that the dynamic stress-strain behavior of the sand is influenced by grain size and strain rate. The deformation process of the sand can be categorized into three stages: elastic, yielding, and plastic. Plastic compaction dominates during the yielding stage, while crushing compaction is significant in the plastic stage. The relative crushing index of particles shows a direct relationship with both strain rate and effective particle size, while it is inversely related to the fractal dimension. The impact of particle size on energy absorption efficiency varies based on particle characteristics such as mineral composition, particle size, and degree of differentiation. At the same stress level, larger particle sizes exhibit higher energy absorption efficiency, and under the same loading strain rate conditions, larger particles experience lower peak stress. To enhance the energy absorption efficiency of sand and decrease the required loading level, it is advisable to utilize sand with larger particle sizes.