The collision characteristics of the truck fences are very important to occupant safety in car, when the car’s front collisions the tail of truck. This study is a kind of the truck fence structure and simulates its crash. First, simulates the original truck guards. Second, improves the truck fence, and the truck fence is simulated by ANSYS / LS-DYNA. Finally, the simulation results and unimproved simulation results are compared. The results show that the dynamic response characteristics (deformation, velocity and acceleration) and the absorb energy (interna energy and kinetic energy) of the improved model are significantly enhanced.