A new method of fabricating high-silica channel optical waveguides using porous silica glass as the starting material is demonstrated. To form the optical guide region, liquid-phase metal alcohoxide is selectively added to the porous glass, followed by consolidation of the porous glass into a transparent glass. Photopolymer, with which the porous glass is soaked and patterned, plays an essential role in the selective doping with metal alcohoxide. The propagation loss of the multi-mode waveguides fabricated by this method was about 2 db/cm. This simple method with find applications in making various optical circuits.