Abstract: In this paper, we aimed at the impact responses of human body during aircraft force-landing by studying the seat-to-body transmissibility using the 11-DOF seated human body model. The impact responses of human body under the vertical impact excitation are examined by numerical simulation approach. The results show that the lumbar spine would be more easily injured than the other part of the body because of more evident response. Moreover, it was indicated that the passenger seat stiffness had obvious influence on the responses of the human body under vertical impact excitation and the appropriate design for the passenger seat stiffness can reduce the impact responses of human body significantly.