A great deal of energy can be absorbed when the inner diameter of a steel tube is inflated by inserting a rigid rod. This procedure has some advantages: high energy absorbed per length, constant compress force and robust to the direction of insertion force. Therefore, this is very fit for energy-absorber for some light vehicles. The effect of energy-absorbing is investigated by impact test and simulation in this paper. Applications for full frontal impact and offset frontal impact of a minibus are discussed.