Aiming at the accident characteristics of the vehicles impact against guardrail on highway, the vehicle-guardrail-road system finite element model containing occupant restraint system is built. By using explicit dynamics finite element method, the impact process of vehicles against double wave guardrail is numerically simulated, then the impact experiment of real vehicle against guardrail is carried out. Factors influencing impact characteristics of the system is analyzed, the law of energy dissipation and absorption of the system is studied, energy absorption of the main parts such as double wave guardrail is also analyzed. With trajectory and injure index of occupant analyzed, drive safety is evaluated. The results show that the study has important practical significance of improving traffic safety facilities and analyzing traffic accidents on highway.