Using the ANSYS software and the Jing Yue Chang-jiang river highway bridge as the research background,this paper sets up the separated steel box girders’ shell element model of three working conditions: the biggest single cantilever,the biggest double cantilever and the second beam assembled completely.Using the spatial finite element method to analyze the shear lag effect of the separated steel box girder in cantilever construction stage,under different conditions,the distribution regularity of separated steel box girder’s shear lag coeffic...