A cross-linked azopolymer with high optical and thermal stability was prepared. A pure polarization grating without surface topology was fabricated from cross-linked azopolymer by polarization holography by use of orthogonal linearly polarized beams from a $\mathrm{He}–\mathrm{Cd}$ laser with a power density of $60\mathrm{mW}∕{\mathrm{cm}}^{-2}$ . The surface relief structure was investigated by atomic-force microscopy, and the polarization grating was observed by polarization optical microscopy. The grating spacing is $1.5\mathrm{\mu }\mathrm{m}$ . The grating is stable at room temperature and can endure repeated writing–erasing.