By considering the limitations of material selection and shielding effect associated with the manufacturing of diffractive optical elements, this study introduces the fabrication of diffractive optical elements based on the rapid prototyping technology of the ultraviolet (UV)-cured organic-inorganic nanocomposites. Thus, we can obtain diffractive optical elements exhibiting a high refractive index and a high dispersion. Further, a composite formulation suitable for manufacturing diffractive optical elements is obtained based on an experiment on the organic-inorganic nanocomposite preparation. The formulation contains aliphatic polyurethane acrylate (2PUA) with mass fraction of 57.97%, pentaerythritol triacrylate (PETA) with mass fraction of 38.64%, photoinitiator 184 (Irgacure 184) with mass fraction of 1.45%, dispersant 163 (Disperbyk 163) with mass fraction of 1.93%, and ITO nanoparticles with controllable mass fraction. Diffractive optical elements are fabricated using this method. The average microstructural height of the mold-core surface of the diffractive optical elements measured using the step instrument is 13.26 μm. Subsequently, we fabricate the UV-cured diffractive optical elements. Further, the average surface microstructural height of the diffraction optical elements using UV-cured organic-inorganic nanocomposites is 12.58 μm. The relative error between the diffraction optical elements and the mold-core microstructures fabricated by the UV-cured organic-inorganic nanocomposites is 5.141%. The manufacturing technology of diffractive optical elements for the UV-cured organic-inorganic nanocomposites overcomes the limitation of material selection and reduces the occlusion error, making it considerably significant for the rapid prototyping of the refractive-diffractive hybrid optical systems in a wide band.