Abstract: The dynamic compressive response characteristics of graphene-reinforced simulated lunar regolith geopolymer were investigated using a Φ50 mm split Hopkinson pressure bar (SHPB) test system with impact velocities ranging from 3.39 to 6.67 m/s and graphene contents varying from 0 to 0.15% (mass fraction). The effect of graphene content on the dynamic compressive strength, energy dissipation characteristics, and fragmentation fractal dimension was systematically analyzed. The microstructural reinforcement mechanisms of graphene in the matrix were characterized by scanning electron microscopy (SEM). The results demonstrate that the graphene-reinforced simulated lunar regolith geopolymer exhibits significant strain rate effects, with both dynamic compressive strength and dynamic strength factor showing linear increases with impact velocity. Under fixed impact velocities, the dynamic compressive strength first increases and then slightly decreases with increasing graphene content, reaching an optimal content of 0.10% (14.75% improvement compared to the control group), while excessive doping leads to strength reduction due to graphene agglomeration. Energy analysis reveals that the incident, absorbed and reflected energies all display initial growth followed by stabilization, with peak incident energies reaching 7.06, 6.66 and 3.67 times the peak absorbed energies at impact velocities of 6.67, 4.49 and 3.39 m/s respectively for the 0.1% graphene content group. Fractal analysis of fragmented specimens confirms highly self-similar distribution patterns of broken fragments. Microstructural investigations indicate that graphene effectively restricts damage propagation through pore-filling and microcrack-bridging mechanisms, thereby enhancing energy dissipation, while simultaneously serving as nucleation sites to accelerate geopolymerization reactions, promoting the formation of C—A—S—H and N—A—S—H gel phases and creating multiscale reinforcement structures. This study provides important experimental support for performance optimization of lunar base construction materials under high strain rate conditions.