In this paper crushing tests of circular and square tubes under impact loading are conducted to investigate the energy absorption ability by using a newly constructed impact machine for crushing tests. The difference between the static and impact crushing behaviours of aluminium specimens is found not significant, while the results of steel specimens are strongly affected by the dynamic effect. The energy absorption ability of steel square tubes under impact loading is much higher than that under static loading because the crushing modes in static and impact tests show a big difference each other, which would come from the strain rate effect of steel, inertia force, imperfection of specimens and so on. It may be difficult to discuss the dynamic/static ratio in crushing tests only by the strain rate effect of material used.The absorbed energy by steel specimens is absolutely higher than aluminium specimens, while the absorbed energy by unit mass shows the advantage of aluminium because the mass density of aluminium is one third of steel. Circular tubes have a better energy absorption ability than square tubes under the condition that the size and area of cross section are approximately equal.