Abstract: In the constructing a long-span self-anchored swivel arch bridge which crossing the existing line，how to obtain reliable cast-in-place main arch special-shaped cap support the temporary structure is a key technical problem in the construction． Therefore，taking the construction of the main arch cast-in-situ frame as the research object，the finite element SAP 2000 was used to build support model，analysed the support stress and deformation characteristics in the process of construction． The results showed that stress and deformation of the arch bridge cast-in-place bracket met the standard requirements，and had withstood the test of real bridge，and that the design and construction of special-shaped cap support is safe and reasonable．