Abstract: The test which a real car bumps against full-scale guardrails is the most intuitionistic and effective way for researching the security of guardrails.But there are some deficiencies such as:high-cost,long-cycle, incompletion repeatability and shortage of test data etc.Car bumping guardrail system has been modeled and simulated,and its results approved by test.Both characteristic data have great coherence.On the basis of the results of simulation,we can deeply analyse influencing factors of car bumping guardrail system.It will be beneficial to the guardrail design,construction,setting and car crashworthiness ameliorating.