Disclosed is a method of producing a planar multimode optical waveguide by direct photo-patterning and, more particularly, to an optical waveguide material and a method of producing the same. It is possible to control the refractive index of the optical waveguide, and the optical waveguide has a desirable refractive index distribution throughout different dielectric regions. In the method, it is unnecessary to conduct processes of forming a clad layer and of etching a core layer, thus a production process is simplified. The method comprises coating a photosensitive hybrid material having a refractive index or a volume changed by light radiation, in a thickness of 10 microns or more, and radiating light having a predetermined wavelength onto the coated photosensitive hybrid material to form the multimode optical waveguide due to a change in refractive index of a portion onto which light is radiated.