Due to the low stiffness of the steel U-shaped girders of composite structure during incremental launching construction, special measures should be taken before the installation of the concrete deck. In this paper, the structural performance of steel U-shaped girder during launching construction was evaluated. The geometric configuration of the steel U-shaped girder was analyzed via transfer matrix method firstly. Then a local stress controlling strategy was developed based on a comprehensive finite element analysis of local stress characteristics. The comparison between predictions and in situ measurements of a large bridge project indicated the validity and accuracy of the proposed method.