Provided are a temperature-insensitive polymeric optical AWG device and method of manufacturing the same. The temperature-insensitive polymeric optical AWG device includes: polymeric grating channel waveguides interposed between free propagation slab regions on a substrate between the input and output waveguides and having different 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; and a shield layer shielding entrances of the hollow trenches so that the polymeric grating channel waveguides do not flow into the hollow trenches.