Abstract: The slag- and fly ash-based geopolymer concrete (GC) specimens were prepared by sodium silicate and sodium hydroxide alkali-activated slag and fly ash，the ordinary Portland cement concrete (PC) specimens were prepared by Portland cement, the 28-day-static compressive strengths of the GC and PC were 56.4 and 61.6 MPa, respectively. Impact compressive experiments were carried out on the GC and PC specimens, respectively, by using a 100-mm-diameter split Hopkinson pressure bar (SHPB) device.The dynamic stress-strain curves in the average strain rate range of 0 to 100 s-1for these two materials were obtained experimentally. These stress-strain curves were compared to explore the dynamic mechanics properties of the GC. The GC takes on favorable impact compressive strength，deformation performance and toughness under impact load. The GC exhibits rate sensitivity, its dynamic compressive strength, deformation performance and toughness increases with the increase of strain rate under impact load. The impact compressive strength and toughness of the GC are less than those of the PC, the deformation of the GC before the specimens start breaking is approximate to that of the PC, while the deformation of the GC after the specimens break completely is less than that of the PC.