Abstract: A gelatin film was applied on the indium tin oxide （ITO）-coated glass substrates which were coated with polyimide （PI） and treated by rubbing. The photoinduced changes of the gelatin film were achieved by exposure to UV lamp through a grating photomask. The gelatin film exhibited grating structure after the development and corrosion disposal. Liquid crystal （LC） was injected into the cell, the polymer/liquid crystal grating was fabricated. The diffraction efficiency of the grating is electrical switchable. The results indicate that the configuration of the grating is good. This method can avoid the inadequacy of phase separation and resolve the irregular phenomena of grating fringe. The on-off of the first diffraction order of the grating is 87:1.The sample shows good switch ability.