The invention relates to a bottom template for a subway floating slab. An embedded hole is formed in a baseplate of the bottom template, a plastic core model is arranged in the embedded hole, a folding edge of the plastic core model is smaller than the embedded hole, the plastic core model and the folding edge are respectively sleeved with a core plate and a counterweight block, the core plate and the embedded hole are consistent in size and are horizontally arranged in the embedded hole of the baseplate, the counterweight block is arranged below the core plate and is smaller than the core plate, support blocks are arranged on a left position and a right position of a lower part between the core plate and the baseplate, and a high-intensity magnet is arranged on the longitudinal position of the lower part between the core plate and the baseplate. By adopting the bottom template, when in mold stripping, as long as the high-intensity magnet is separated from the baseplate, since the folding edge of the plastic core model is smaller than the embedded hole, a product, the plastic core model and the core plate can be easily separated from the embedded hole, the product and the plastic core model are not damaged, and the appearance and quality of the product and the utilization rate of the plastic core model can be improved.