One of the most important tasks in the study of cable-stayed bridge monitoring and testing is to establish an accurate and reliable baseline FE model. This model should be updated, since it should make factors such as its cable force and displacement align with the monitoring and testing results. At present, various methods of updating the FE model mostly require iterative calculations, considering the huge calculation workload and the difficulties in achieving such goals. In order to resolve this situation, a new model-updating method is put forward by using ANSYS and MATLAB, and combining an influence matrix and optimization algorithm. This approach does not require iteration to acquire parameters such as cable force, displacement, etc., which are fitted to the measured parameters. As illustrated by example, this method is verified to be feasible and easy to realize.