Based on the theory of slab track-roadbed system coupling dynamics，a semi-spatial timing coupled vertical roadbed-slab track interaction model is developed，and the dynamic properties of slab tracks used in high-speed railways are investigated. The effects of the elasticity and damping of the CA layer and stiffness of fastener-rubber pad structures under the slab on system dynamics are also analyzed. The spring-damping properties of fastener-rubber pads system and CA layer have influenced greatly on the dynamic characteristics of the track structure and roadbed system. The dynamic properties of the track and roadbed can be improved to reduce the stiffness of the fastener-rubber pad structures，or increase the thickness of the CA layer.