In order to investigate the coordinated deformation performance of ballastless tracks on the Dongying Yellow River highway and railway cable-stayed bridge with a main span of 600 m, a detailed numerical model of the bridge-track system was established by using commercial finite element software. The mechanical behavior and coordinated deformation mechanism of the system were analyzed in terms of bridge stiffness, rail longitudinal stress, longitudinal slip of fasteners, and relative deformation between layers of ballastless tracks to determine whether they comply with the standards. Furthermore, the influence of the fastener resistance and rubber isolation layer stiffness on the coordinated deformation performance of the system was studied, and corresponding optimization recommendations were provided. The research results indicate that the vertical stiffness of the bridge is sufficient under all working conditions, with the deflection-span ratio, minimum vertical equivalent curvature radius, and beam-end rotation all complying with the standards. The rail strength, upon verification, does not exceed the allowable stress, and setting both ends of the rail free can effectively simulate the stress release function of rail expansion joints. Compared to using low-resistance fasteners, the longitudinal slip remains within the linear elastic range under all working conditions when using normal-resistance fasteners, reducing the risk of fastener failure. Thus, it is recommended to use normal-resistance fasteners or redesign suitable low-resistance fasteners. The compression deformation between layers of ballastless tracks is inversely proportional to the isolation layer stiffness, while the separation deformation between layers of ballastless tracks is directly proportional to the isolation layer stiffness. It is recommended to use a rubber elastic cushion with a body stiffness of 0.1 N/mm³ as the isolation layer. In such case, the maximum compression and separation deformation between the layers of ballastless tracks do not exceed the limits under all working conditions, indicating that the bridge-track system has excellent coordinated deformation capability, which is beneficial for extending the service life of ballastless tracks. The studied bridge-track system exhibits satisfactory mechanical behavior and coordinated deformation performance under all working conditions by using ballastless tracks with recommended parameters. The research findings offer theoretical basis for the feasibility of laying ballastless tracks on the studied bridge, and offer data support for improving the relevant technical standards of laying ballastless tracks on high-speed railway cable-stayed bridges.