Abstract: Quasi-static axial compression tests were performed to study failure modes and energy absorption characteristics of extruded magnesium alloy AZ31B rectangular tubes. The effects of tube length, section size and chamfer initiator on energy absorption were investigated. The results showed that the crushing response of magnesium alloy tubes can be categorized into two basic modes: global fracture mode and progressive fracture mode. The unchamfered tubes tend to take the global fracture mode, while chamfered tubes present progressive fracture mode starting from the tube end with chamfers. The progressive fracture mode is favorable for energy absorption. Magnesium alloy tubes exhibit good energy absorption capabilities and outperform other tubes like steel tubes, aluminum alloy tubes and composite tubes in terms of specific energy absorption.