The utility model relates to a fiber material-reinforced material-saving, environment-friendly, lightweight and high-strength building formwork. The building formwork comprises a core layer, a surface layer I and a surface layer II, wherein a reinforcing layer I is compounded between the front surface of the core layer and the surface layer I, and a reinforcing layer II is compounded between the back surface of the core layer and the surface layer II; and the core layer is of a foamed plastic plate, the reinforcing layer I and the reinforcing layer II are of fiber cloth, and the surface layer I and the surface layer II are of plastic plates. According to the building formwork disclosed by the utility model, the plastic plates are taken as materials of the surface layers, so that the building formwork has the advantages of excellent shock resistance, rigidity, flame resistance and water resistance, as well as higher surface smoothness. The fiber cloth is used for reinforcement between the core layer and the surface layers, so that the strength is higher. A plastic foam material is taken as the material of the core layer, so that the weight per unit area of the formwork is reduced. The surface layers and the core layer adopt recoverable polypropylene and other materials, so that the manufacturing cost is reduced. The building formwork disclosed by the utility model has the advantages of good physical and mechanical properties, capability of being recycled for multiple times, small apparent density and convenience in operation, is favorable for improving the construction efficiency, saving the materials and realizing an environment-friendly effect, and can be widely used for concrete pouring construction.