In view of the in creasingly serious environmental vibration problem of urban rail transit, this paper takes the rubber floating slab, a commonly used vibration isolation measure in urban rail transit, as the research object, and studies and improves its low -frequency control performance from the perspective of elastic waves. The periodic boundary conditions of the rails are modelled using plane wave series, and the energy generalisation of full-paved, strip-paved, and point-paved rubber floating plate track structures is calculated using the energy method，the band gap characteristics of the rubber floating plate are finally obtained by scanning the wave number variations. The periodic boundary conditions and positive symmetrical boundary form constraint matrices, and the linear expression method is adopted to process the boundary conditions to obtain the unknown coefficients that can be varied. By scanning the variation, the bandgap characteristics of the rubber floating slab are obtained. The accuracy of the proposed method is verified using the finite element method. The results show that the cut-off frequency of the first order band gap of the full-paved type is the largest, and the strip-paved type and the dot-paved type have lower cut-off frequency and wider passband bandwidth. The cut-off frequency of the first order band gap increases with the increase of the stiffness of the rubber pad. The dynamic vibration absorber for floating slab accurately controls the elastic wave, providing new ideas and methods for the application of low-frequency vibration control of rubber floating slab tracks.