In the present study, the effect of geometrical parameters of two different types of aluminum thin -walled structures on energy absorption under three -bending impact loading has been investigated experimentally and numerically. To evaluate the effect of parameters on the specific energy absorption (SEA), initial peak crushing force (IPCF), and the maximum crushing distance (delta), a design of experiment technique (DOE) with response surface method (RSM) was applied. Four different thinwalled structures have been tested under the low -velocity impact, and then they have simulated by ABAQUS software. An acceptable consistency between the numerical and experimental results was obtained. In this study, statistical analysis has been performed on various parameters of three different types of tubes. In the first and the second statistical analysis, the dimensional parameters of the cross-section, the number of holes, and the dimensional parameter of holes were considered as the design variables. The diameter reduction rate and the number of sections with different diameters are related to the third statistical analysis. All design points of the statistical method have been simulated by the finite element package, ABAQUS/Explicit. The final result shows that the height and thickness of tubes were more effective than other geometrical parameters, and despite the fact that the deformations of the cylindrical tubes were around forty percent greater than the rectangular tubes, the top desirability was relevant to the cylindrical tubes with reduced cross -sections.