Abstract: The debonding of emulsified cement asphalt mortar is one of the main damage types in longitudinally connected slab track turnouts of bridges. Based on the structure of No. 18 turnout, vertical-coupling models for longitudinally connected slab track turnouts are established for both static and dynamic analysis. Influences on the deformation and force of the track from different degrees of debonding underneath prefabricated slabs are analyzed using the finite element method. The study shows that debonding underneath prefabricated slabs has more significant impacts on prefabricated slabs and rails than on concrete bases. Different forms of debonding have different degrees of influence on the track. When the debonding occurs at the ends of the slab, the force and deformation of the track are greater. On the other hand, when the debonding occurs in the middle of the slab, the warping displacement of the slab is not obvious. Furthermore, the influence of the size of debonding on the track is analyzed, and critical dimensions of the debonding are proposed. The height of the debonding should be less than 1.8mm and the length less than 0.7m.