The acceleration waveform of the experiment and simulation has differences in the energy absorbing area of the crash box. Comparing the acceleration waveform in the experiment, the peak and pulse width in simulation are higher and narrower respective- ly. The accuracy of simulated results isreduced largely. According to differences in acceleration waveform of Changan vehicle frontal im- pact, crash box is taken as the research object to establishthe sled FEA model, the sled test design parameters in certain condi- tions. Effecting parameters, includes deflection angle of sled, plywood material, movement style of tires and stamping hardening of ma- terialin the energy absorbing process. The results show: Having correlations between acceleration waveform and those parameters, the optimized acceleration peak is reduced to 10g in simulated result, and the optimized model can reasonably predict the trend of accelera- tion waveform. It decreases the differences and costs effectively, The FEA model of the crash box is used to design the physical parts.