Based on the structure and working principle of a hexagonal spring tube energy-absorbing device for car crash, this paper utilized the SolidWorks, Hypermesh and LS-DYNA to establish a finite element model for the device, and analyzed the performances of the device, under a frontal crash condition whose weight is 1.5 tons and speed is 50 km/h. Simulation results have shown that the energy-absorbing device have very good performances. For example, a smaller invasive amount for car stringer(252.9 mm), a higher crashing energy absorption ratio(52.09%) and a lower maximum X-direction acceleration for car(58.8 g).The above indices show that the device can protect the vehicle and the people in the vehicle.