The invention relates to big unit type track slabs of a ballastless track. The tensile and compressive stresses of the components of the track slabs of the ballastless track are not completely the same along with temperature variation, thus causing deformation differences of the components and even bed slab cracks and fracture and affecting the smoothness and service life of the track. The track slabs are characterized by utilizing permeable true expansion joints to divide the bed slab of the ballastless track into a plurality of big unit slabs and then utilizing impermeable dummy expansion joints to divide the big unit slabs into a plurality of small unit slabs to fit with impermeable dummy expansion joints which are arranged on a supporting bed and correspond to the true and dummy joints on the bed slab to mitigate deformation of the track slabs caused along with variation of environmental factors through synergy. The big unit type track slabs have the following advantages: the big unit structures of the track slabs reduce the tensile and compressive stresses generated inside the bed slab, thus avoiding over limit, over standard and irregular cracks caused by continuous structures of the track, especially avoiding bed slab arching happening in the extreme high temperature seasons and ensuring the smoothness and safety of the track.