The invention discloses a fabricated bi-directional prestress hollow slab and a manufacturing method thereof. The fabricated bi-directional prestress hollow slab comprises an I-shaped slab basic body, a steel bar assembly, spliced steel bars and laminated layers. A pre-tensioned prestressing method is adopted on an industrial long-line pedestal, a produced prestress I-shaped slab is conveyed to a construction site, transverse prestress tendons penetrate through the produced prestress I-shaped slab, and splicing is conducted through the post-tensioned bonded technology; after the unidirectional prestress I-shaped slab is assembled, a rectangular three-dimensional cavity composed of a bottom surface slab, an upper surface slab, longitudinal ribs and transverse ribs of the I-shaped slab is a hollow of the slab; and a reliable pull rod system is composed by longitudinal prestress tendons of the I-shaped slab and the assembled transverse prestress tendons. According to the fabricated bi-directional prestress hollow slab, the load force transferring route of the fabricated bi-directional prestress hollow slab is definite, structural continuity, ductility and overall stability are enhanced, and the anti-collapse and anti-seismic properties of the structure are improved.