Provided are a temperature-insensitive polymeric optical AWG device and a method of manufacturing the same. The temperature-insensitive polymeric optical AWG device includes: a substrate; an input waveguide formed on the substrate; an output waveguide formed on the substrate so as to correspond to the input waveguide; polymeric grating channel waveguides interposed between free propagation slab regions on the substrate between the input and output waveguides and having difference lengths; a plurality of hollow trenches formed by selectively etching a surface of the substrate under the polymeric grating channel waveguides and allowing the polymeric grating channel waveguides to freely thermally expand from the substrate depending on a temperature variation so as to compensate for refractive indexes of the polymeric grating channel waveguides varying with the temperature variation; and a shield layer shielding entrances of the hollow trenches so that the polymeric grating channel waveguides do not flow into the hollow trenches, so as to separate the polymeric grating channel waveguides from the substrate.