Dynamic mechanical tests were carried out on EPS concrete at early ages (12 h、24 h and 36 h). Whereafter, the influences of impact velocity (4.5~6.5 m/s) and age (12 h、24 h and 36 h) on impact resistance of EPS concrete were analyzed in terms of dynamic compressive strength, peak strain, ultimate strain and energy dissipation density. Additionally, the properties of EPS concrete at early ages were compared with that at the age of 28 d. The results show that the dynamic compressive strength, peak strain, ultimate strain, and energy dissipation density of EPS concrete have an impact on the velocity-strengthening effect. With the increase of age, the dynamic mechanical property indicators of EPS concrete and its sensitivity to impact velocity increase. At the age of 28 d, the dynamic compressive strength, peak strain, ultimate strain and dissipation density of EPS concrete are the maximum, and its sensitivity to impact velocity is the strongest. EPS concrete has good deformation and energy absorption characteristics at the early age. At the age of 36 h, the peak strain, ultimate strain and energy dissipation density of EPS concrete can reach 66%~82%, 91%~93% and 72%~78% of that at the age of 28 d, respectively.