The finite element model of the construction process of a large－span steel truss factory is established by using finite element analysis software MIDAS/GEN. The track simulation analysis was carried out during the construction process. The internal force and deformation of components of structural system under various operating conditions were obtained. The results show that the maximum internal force and deformation of components appear in the first working conditions in the process of ascension. The analysis results have some reference value for the implementation of the construction plan.