In order to study the force performance of the whole bridge of Wulong River Bridge in the background project, a full-bridge frame model for continuous beam-arch combination system is proposed in ABAQUS. Linear elasticity analyses of the Midas model and the ABAQUS rod model are carried out to verify the accuracy of the proposed finite element model. The consideration of both structural nonlinearities and geometric nonlinearities of the entire bridge has been taken into account to investigate the mechanical behavior of continuous girder-arch combination systems. The findings indicate that: during the linear stage, the internal forces in the cross-sections of the two models at each construction phase are in agreement, and the stress distribution is similar; after taking into account the nonlinearity, the maximum reduction of the load scaling factor K is 16.7%, indicating that the nonlinearity of the structure has a significant impact on its force behavior.