The invention relates to a construction method for a double-block-type ballastless track bed slab, which comprises the following steps: 1, clearing a base surface and performing construction lofting; 2, placing a bottom layer of reinforcing steel bars, and laying sleepers; 3, mounting a tool track and adjusting the sleepers; 4, assembling track panels; 5, coarsely adjusting the track panels; 6, binding the reinforcing steel bars and performing earthing welding; 7, mounting templates and finely adjusting the track; 8, casting concrete into the track bed slab; 9, loosening adjusting devices and fasteners, and curing the concrete; and 10, relocking the tool track and completing the measurement. The construction method has the advantages that: the tool track is adopted as a detection standard, so the precise positioning of the track is realized; a frock system is simple, is easy to process and manufacture, has wide commonality, and is not only suitable for construction of the track bed slab in a subgrade section but also suitable for construction of the track bed slab in a bridge section; the construction process is simple and quick, and various working procedures are easily carried out by flow construction; and the construction cost is low, so the construction investment is effectively saved.