In order to analysis the impact compatibility of 2 passenger vehicles whose parameters and appearance are similar,the evaluation of rear-end impact compatibility was ensured based on existing rear-end crash test regulations.The rear-end impact test of 2 passenger vehicles was analyzed through the aspects of preparation and process of rear-end impact compatibility testing.The result showed that incompatibility existed in test vehicles because the difference of structural rigidity and production standards.Even the maximum acceleration of vehicles are qualified,passengers can not be protected because the components of vehicles have intruded into passenger compartment.