To study the effect of EPS on the toughness of plain concrete, the EPS concrete with 10%，20%，30%，40%，50% EPS volume fraction were prepared. Taking specific energy absorption as the index, the toughening effect of EPS with different EPS volume fraction under impact loading were studied using a 100mmdiameter split Hopkinson pressure bar（SHPB）apparatus, and the toughening mechanism of the concrete was discussed. The results show that the toughness of the EPS concrete improves with increasing average strain rate, which shows obvious strain rate dependence. The toughness of EPS concrete improves in some degree with 10%30% volume fraction of EPS. And the optimum volume fraction of EPS is 20%. Its toughing effect reduces somewhat when the EPS volume fraction reaches 40%50%.