Abstract: Due to the frequent occurrence of debris flow disasters along railways and highways,the buildings and structures are often severely damaged due to the inclusion of boulders.An improved composite structure with brace-steel cable network is proposed,which can realize the “water-stone separation” in debris flow disasters and mainly intercept the boulders in debris flow.The dynamic response and failure modes of the structures were analyzed by finite element software.The results show that the structure has a certain impact resistance,which can intercept debris flow boulders.For the structure with lateral support,the element failure first occurs at the inner side of the joint between the supporting steel pipe and the steel pipe column on both sides.For the structure with large lateral support and the structure with small lateral support,the tensile failure occurred at the outer side of the restrained columns at both sides,especially the deformation of the support pipe with small lateral support is obvious.The plastic strain of steel tube is obvious at the joint of steel tube and steel strand in the steel braced cable-net composite structure.The experimental results of displacement and acceleration are in good agreement with the simulated results.The numerical simulation method is reasonable.This kind of supported structure can be used to prevent the impact of debris flow.