The major applications of LDHs based on the intercalation or exchange of specific guests as absorbents have been reported. However, it is seldom discussed to apply as optical materials. In this work, we have studied the Mg–Al LDH mixed with nematic liquid crystal and photo-polymer matrix. Photo-polymerization was induced by argon ion laser irradiation on the filled cells, which contain photo-initiator, monomers, liquid crystals and Mg–Al LDHs. Diffraction efficiency makes apparently increasing from 1.4 to 5.6 % . When the sample was added 1 phr of Mg–Al LDH, the diffraction efficiency rise to 5.6 from 1.4 % , compared with original PDLCs. Polymerization induced the phase separation of polymer and liquid crystal in the PDLC film. Higher diffraction efficiency was observed when PDLC hybridized with inorganic LDH, which will change the polymerization rate of PDLC, and help the formation of the grating effect; therefore, the diffraction efficiency of the whole system was improved. The noteworthy factor of improving diffraction efficiency will be discussed in this paper.