Abstract: This research addresses the need for efficient energy-absorbing components in civil engineering by designing a gradient aluminum foam-filled aluminum alloy composite tube ("composite tube"). Using drop hammer impact tests and numerical simulations, the energy absorption characteristics of the composite tube under impact loading were evaluated. Research results show that the composite tube significantly outperforms hollow tubes, with a 135.76% increase in initial peak force (F_M), 95.01% increase in platform force (F_P), and 20.92% improvement in load efficiency (CFE). The study further explores the effects of foam layer number, of gradient distribution, and of impact velocity on energy absorption. A 10-layer gradient foam composite tube showed a 13.63% reduction in the peak load, compared to a uniformly filled tube, and a positive gradient configuration improved energy absorption by 6.55%. The stable energy absorption performance of the composite tube under various impact velocities offers new perspectives for developing energy-absorbing components.