The longitudinal linkage of the floating slab track （FST） has weakness due to the dynamic effects of FST longitudinal linkage， which are not adequately considered in the track design. By introducing the method of equivalent density and equivalent foundation coefficient to simplify the model of the base of a steel-spring-FST system， a three-dimensional finite element model of vibration characteristics analysis of prefabricated short and cast-in-situ FST system is established. In the proposed model， the influ? ence of the rail， shear hinge， and foundation under the slab on the vibration characteristics of the floating slab structure is fully con? sidered. The modal analysis and harmonic response analysis are analyzed with a focus on the dynamic effect characteristics of the longitudinal connecting slab of the FST system. The results show that： The modal shape of the FST in the low frequency band of 1~200 Hz mainly shows four types of motion： rigid body motion， bending， bending-torsion combination and torsion； For the pre? fabricated slab track system， the frequency band in which the floating slab dominates the vibration characteristics of the system con? forms the system modal analysis and harmonious response analysis； For the cast-in-situ slab track system， when the frequency is within 32.6~57.8 Hz， the frequency band is the transition band， where the dominant role of the FST in the vibration characteris? tics of the system is weakened； The lower-order bending modes generated by the coupled slab dynamic effect are expressed as rigid body motion modes in the prefabricated slab system； for the FST composed of Ns slabs， the number of additional modes around each order of bending mode frequency of a single slab caused by the coupled slab effect is Ns/2?1.