The dynamic response, blast resistance and energy absorption capability of clamped square sandwich panels comparing two aluminum alloy face-sheets and a layered gradient metallic foam core, subjected to air-blast loading, were studied numerically in this paper. Graded sandwich specimens with six different core-layer arrangements and three different face-sheet thickness arrangements were examined, respectively, compared to those ungraded sandwich panels with an equivalent nominally mass. Simulation results show that the blast resistance and energy absorption capability of sandwich panels with layered gradient metallic foam cores could be improved by optimizing the arrangements of different density metallic foam core-layers, and the graded sandwich panel with low-middle-high density core configuration has the best blast resistance capability. The blast resistance of graded sandwich panels with different thickness arrangements for top and bottom face-sheets has no obvious change tendency, since the normal stress distributions of their sandwich cross sections are controlled simultaneously by face-sheets and gradient foam core.