The invention discloses a biodegradable collagen-based cornea substitute and a preparation method thereof. The substitute is obtained as follows: collagen and a macromolecular polymer are subjected tocompound crosslinking treatment in a aqueous phase and then cured by a mol; or the collagen and the macromolecular polymer are subjected to electrospinning to form a nanofiber membrane, the nanofibermembrane is further subjected to compound crosslinking and drying to form a 3D cornea scaffold, and the 3D cornea scaffold is used after rehydration swelling clinically. The cornea substitute has controllable degradability, good phototropism and mechanism strength and significant induction functions on increase of corneal epithelial cells and corneal corpuscles.