Chinese Xizang-style historic buildings, represented by the Potala Palace architectural complex, are one of the important forms of architectural heritage. Their structures mainly consist of stone masonry walls and timber frames. These are typical stone-timber structures with dual load-bearing systems. The design and construction often lack consideration for lateral horizontal loads, leading to poor overall structural integrity and susceptibility to out-of-plane failure of components. Understanding the behaviour and dynamic response of such historic structures is useful for the evaluating the techniques used for their conservation and rehabilitation. This study focused on typical stone-timber structures in Xizang-style historic buildings. It briefly introduced the structural characteristics and discussed the applicability of the 2D Discrete Element Method (DEM) for modeling these structures. The study specifically analyzes the differences between separated and integral wall modeling, as well as the impact of wall tapering on structural stability. Structural analysis includes stress distribution under self-weight and dynamic response to harmonic excitation. Based on the results, key factors affecting structural stability and potential collapse mechanisms under strong earthquakes were identified, providing a basis for conservation efforts of historic buildings.