We report on theoretical study of diffraction efficiency of holographic polymer dispersed liquid crystals (H-PDLCs) subject to externally applied electric field. To find the director profile within single liquid crystal (LC) droplet under externally applied voltage we used Monte Carlo simulations, Lebwohl-Lasher (LL) lattice model strong tangential (bipolar droplets) and normal (radial droplets) anchoring conditions. The coupled-wave theory is then used to describe the diffraction properties of anisotropic holographic gratings under the action of the electric field.