Taking a newly-built bridge project as the background, the spatial finite element software Midas Civil is used to establish a carling model. The 3D finite element software ANSYS is used to analyze the crossbeam stress under the multiple construction conditions, and each result is compared and analyzed. The result shows that the strain result of crossbeam is distorted in the existing crossbeam design method because of not considering the longitudinal effect according to the strain control viewpoint. In order to guarantee the safety and durability of bridge structure in the service period, the analysis mode should be used by considering the vertical and horizontal interactions. The relevant conclusion can provide a certain guiding significance for the design and analysis of crossbeams in the future.