In this study, the method of analyzing the thin-wall crashing box of impact attenuator for student formula is proposed by the means of simulation and validation following Formula Society of Automotive Engineers-SAE rules. The analysis was performed based on computerized simulation software for calculated the absorption capacity of the simple and multiple cell of thin-walled tubes. The effect of thin-wall thickness consisted of 1.2 mm, 1.6 mm and 2.0 mm was also evaluated. The simulation results as energy absorption, crashing force efficiency, and absorbed energy per unit mass were identified among nine patterns. According to the results, the increase of interior cell number and the wall thickness contribute the absorbed energy ability. However, the increment of wall thickness lead to the increase of crashing force magnitude. Regarding the kinetic energy, a 2×2 multiple cell box with the thickness of 2 mm is designated for construction and verify. In addition, the quasi static test was set up using the universal testing machine for the numerical validation. The result revealed that the deformed shape including the load-deflection were in the same trend.