The invention belongs to the field of prefabricated buildings, and discloses a prefabricated laminated slab design method, an assembly and disassembly method and a prefabricated laminated slab. The design method comprises the following steps: selecting a distance S as a rib outlet distance of the prefabricated laminated slab; adopting an equal-strength substitution formula to unify the spacing of the steel bars of the prefabricated laminated slab to be S, 0.75 S or 0.5 S; when the distance between the reinforcing steel bars of the prefabricated laminated slab is S, the reinforcing steel bars entering the support are arranged according to the distance S; when the distance between the reinforcing steel bars of the prefabricated laminated slab is 0.75 S, firstly arranging the reinforcing steel bars with the reinforcing steel bars being exposed according to the distance S, and then arranging one reinforcing steel bar without reinforcing steel bars between every two reinforcing steel bars with the reinforcing steel bars being exposed every 2S; and when the distance between the reinforcing steel bars of the prefabricated laminated slab is 0.5 S, firstly arranging the reinforcing steel bars according to the distance S, and then arranging one non-reinforcing steel bar between every two reinforcing steel bars. By unifying the rib outlet distance, the hole opening distance in the mold is unified, the mold can be repeatedly used, the standardization and utilization rate of the mold are improved, the number of times of factory mold opening is reduced, the mold cost is reduced, and the mold and project manufacturing cost is saved.