FRP tubes are specified as application to automobile and aircraft structure because of high energy absorption performance, so that it is necessary to understand energy absorption mechanisms of composite tubes. We have developed prediction method for the crash-related energy absorption capability of the composite tubes. In this study, three types of numerical models were proposed in order to evaluate the energy absorbed by three different major fractures. The analytical method was applied to CF/PEEK and GF cloth/epoxy composite tubes. These analytical results were compared with experimental results. According to comparison between them, the energy absorption mechanisms could be estimated quantitatively.