Abstract: This paper takes the bulging-type energy-absorbing structure for rail vehicles as the research object. Numerical simulations are carried out on energy-absorbing structures with different structural parameters, and the effects of wall thickness, inner diameter and length of energy-absorbing tubes on the crashworthiness of the structure are systematically analyzed. The results show that the wall thickness and inner diameter of the energy-absorbing tube are the key parameters affecting its crashworthiness. The average crushing force increases with the increase of wall thickness and decreases with the increase of inner diameter. Under the same crushing displacement of the energy-absorbing structure, the energy-absorbing capacity rises as the wall thickness increases. In contrast, the length of the energy-absorbing tube has no significant influence on crashworthiness. This study provides a theoretical basis for designing high-performance energy-absorbing structures, and possesses important engineering application value for improving occupant protection and car-body structural safety during rail-vehicle collision accidents.