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Large area of free-standing sol-gel film transmission gratings were obtained by applying poly-α-methylstyrene as thermal degradation sacrificial layer.Photosensitive sols were obtained through sol-gel method using tetrabutylzirconate (TBOZ) and methyltriethoxysilane (MTES) as hybrid precursors and benzoylacetone (BZAC) as chelating agent.The ZrO2-SiO2 hybrid sol-gel films with negative photoresist properties were prepared by dip-coating or spin-coating method when the sols were aged enough.Grating patterns with the duty ratio of 1∶1 and periods of 20 μm, 10 μm and 4 μm were fabricated by ultraviolet (UV) mask irradiation and leaching.The changing of UV absorption band, chemical composition, and the refractive indices of films were investigated.The period, groove depth, and roughness of grating patterns on substrate were characterized.All the films showed an absorption band at around 336 nm which was attributed to the chelate rings originated from the chelating reaction between TBOZ and BZAC.The intensity of absorption band decreased gradually with increase of the irradiation time and it disappeared after 35 min irradiation.The refractive indices of hybrid films decreased from 1.82 to 1.57 with increase of the content of MTES.The periods of grating patterns deviated ~ 0.2% compared to the mask, the groove depth was ~ 204 nm, and the line roughness of grating surface was ~ 10 nm.The organic groups of films and the PAMS sacrificial layer were removed after 330℃ heat treatment.The area of free-standing sol-gel film transmission gratings can reach to hundreds of microns.