Abstract: The influence of human body on dynamic characteristics of the structure is analyzed in this research. Object of this study is a simple beam and the shaker is used as background excitation. The acceleration responses of beam were measured when person in static state (passive person) or in active state stood (active person) on the beam. The dynamic parameters of the structure were identified from a correlation analysis between observed amplitudes and theoretical amplitudes. The results show that, for the person-structure coupled system, nature frequency of the structure is decreased and damping is increased. Moreover, the increase of damping with passive person is bigger than that with active person.