The invention discloses a prefabricated concrete bottom plate with stiffening cold-bending thin wall type steel ribs and a made composite slab. The prefabricated sconcrete bottom plate comprises prefabricated bottom plate transverse structural reinforcement, prefabricated bottom plate longitudinal stress reinforcement, longitudinal stiffening cold-bending thin wall type steel ribs and stiffening cold-bending thin wall type steel rib structural reinforcement; the two longitudinal stiffening cold-bending thin wall type steel ribs same in shape penetrate through holes reserved in the lower portions of the ribs through the transverse structural reinforcement and are connected with the upper portions of the two ribs through the stiffening cold-bending thin wall type steel rib structural reinforcement, and the prefabricated bottom plate transverse structural reinforcement, the prefabricated bottom plate longitudinal stress reinforcement and the longitudinal stiffening cold-bending thin walltype steel ribs are embedded in high-strength concrete to form the prefabricated concreted bottom plate. Accordingly, manufacturing is easy and convenient, rigidity is large, industrial production isfacilitated, and the made composite floor with the stiffening cold-bending thin wall type steel ribs has the advantages that convenience is brought to construction, the bearing capacity is large, theanti-seismic property is good, forms are saved, the floor mass is reduced, and the floor heat preservation, therm insulation and sound insulation functions are added.