Holographic storage characteristics of the hydrophilic Mg(OH)2 nanoparticle dispersed acrylamide-based thick photopolymer are studied. It is illuminated under the incident wavelength of 514 nm of Ar+ laser. Experimental results show that, not only the samples dimensional stability can be improved during the holographic exposure, but also the diffraction efficiency and other performance parameters can be improved in the hydrophilic Mg(OH)2 nanoparticles dispersed photopolymer compared with those traditional samples. There exists the optimum concentration of Mg(OH)2-nanoparticles that maximize diffraction efficiency to 93.7%, the maximum refractive index modulation is 2.13×10-3 and volume shrinkage reduces to 1.61%. The analog image is stored in the materials and reconstructed holograms have good fidelity. All of the results demonstrate that the Mg(OH)2 nanopartical dispersed acrylamide-based photopolymers is an effective material to improve the holographic properties.