In urban rail transit structures, spring vibration isolators are typically installed beneath floating slabs to reduce vibration transmission and ensure stable and safe train operation. However, due to the long-term and repetitive loading of trains, the spring isolators may become damaged or suspended, making them difficult to detect during inspections as they are concealed components. A vehicle-track coupled model was established using ABAQUS finite element software, and the measured vibration data of a certain section of the Shenzhen Metro floating slab was selected to validate the model. The uniform design method was used to conduct parameter experimental design on different damage quantities, degrees, and locations of the spring isolators. The quantitative impact of each damage parameter on the vibration response of the floating slab was obtained through model simulation and calculation. The calculation results show that the location of damage to the spring isolator has the greatest impact on the acceleration and displacement of the floating slab, with influence weights of 50% and 49.3%, respectively. Next is the damage quantity, with influence weights of 28.4% and 27.9%. Lastly, the damage degree has an influence weight of 21.6% and 22.8%. The research results can provide reference for the design of vibration isolators in urban rail structures and the safety monitoring of train operations.