Abstract: Because the deep-foundation-pit and the depth in the project, and it forms the supporting system of internal bracing. It makes the earthwork excavation to be speeially extremely difficult. Therefore, the first supporting system will com- bine structural designs and application of the trestle bridges. It will become the structural styles inevitably. The article based on the building structural design principles, carried on the analysis of the overall stress situation of the supporting system of inter- nal bracing through summaring the common form of trestle bridge structure. Combined with the projeet example, the design methods of supporting system of trestle bridge braeing construction in deep-foundation-pit is introduced, It provided some ref- erences for the structural designs of trestle bridge bracing.