Abstract: There is an urgent requisite on the preservation of Chinese architectural heritages, since environmental and time impacts have been abating their structural resistance capability. Based on the experimental studies on an ancient timber structure in the proceeding companion paper, a semi-rigid element is defined and a 3-dimensional FEM model is developed in this paper. By comparing with measured results, the stiffness of semi-rigid element is deduced and dynamic characteristics of the front tower over Xi'an City Wall are obtained.