The present invention relates to an optical waveguide having a curved reflecting mirror surface for optical coupling and a method of manufacturing it. The method of manufacturing an optical waveguide includes the steps of coating a transparent glass substrate with a photosensitive material; radiating ultraviolet rays onto the photosensitive material through a mask in which the shape of the optical waveguide and partition blocks formed beside ends of the optical waveguide are patterned; manufacturing a photoresist stamp by developing patterns onto which the ultraviolet ray has been radiated through the mask; forming a PolyDiMethylSiloxane (PDMS) mold by coating the photo stamp with PDMS, and forming a core; forming the optical waveguide, in which the partition blocks are formed beside the ends thereof, using the PDMS mold; and dropping liquid polymer between the partition blocks formed beside the ends of the optical waveguide using an inkjet header and hardening it. This structure and manufacturing method have advantage in that optical waveguides having variously shaped reflecting mirror surfaces are simply and economically manufactured.