In horizontal hybrid wooden structures with RC core, the wooden diaphragm is not enough stiff, so the seismic response of wooden parts is dynamically amplified. In this paper, the effects of the axial rigidity of wooden girders and their joints on the wooden diaphragm are shown by comparing the results of modal analysis of shear model and bending shear model. Finally, criteria for seismic force distribution and displacement of wooden diaphragm on dynamic properties, that can be applied to practical structural design, are proposed.