In this paper,using FEA simulation,resolve the problems those appear abnormal deform during the FRB test.The low-er section of drivers chest may be bad intrusion of steering columnresulting from heavy deforms of front floor.Those phenomena all are not accordance with our expectation.We find out the reason causing abnormal distortion exactly by using CAE method and disassembling test vehicle.And propose effective modifications using in following test vehicles those do not occur abnormal deform in follow FRB test.