Not only occupant protection but also pedestrian protection is one of hot issues in vehicle safety. Recently regulations for pedestrian protection have been tightened and the corresponding assessment protocol for pedestrian protection has been also revised. Because of current TRL leg form’s limited bio fidelity, in recent years Flex-PLI which provides extended injury assessment capabilities was proposed. Current TRL leg form will be superseded by Flex-PLI for future pedestrian GTR and Euro-NCAP within couple of coming years. In this study, using CAE simulation injury mechanism of Flex-PLI was investigated and countermeasure for lower leg protection was proposed. It is expected that advanced study for Flex-PLI conducted in this paper results in improving leading technology for future pedestrian protection.