Thin-walled tubular structures are commonly used in automotive and aerospace applications because of their high strength and lightweight characteristics. In this paper we propose a new bionic bi-tubular thin-walled structure (BBTS) inspired from the internal structure of the lady beetle elytron. Six types of BBTSs with different geometric parameters and same type of material were simulated under axial dynamic impact loading with a weight of 500 kg and a velocity of 10 m/s using nonlinear finite elements. The comparison between BBTSs with equal mass shows that the thickness of the inner wall and the cross-sectional configurations influence significantly the energy absorption of the structure. BBTSs show an optimized crashworthiness behavior when the inner wall thickness is between 1.6 and 2.0 mm. In addition, circular and octangular BBTSs show improved absorption characteristics when the inner wall thickness is 2.0 mm. We also evaluate the energy absorption of periodically distributed BBTS against cellular configuration with irregular topology. The energy absorption characteristic of BBTS with regular distribution is better than that of BBTS with irregular distribution, which indicates that the optimized regular structure has an improved mechanical performance to the original bionic topology.