Based on the coupled mode theory for polarized waves inside crystals and the linearized band transport model for photorefractive effect, the analytical expression of the dynamic range parameter, M/#, of a photorefractive crystal in a volume holographic momory is derived. Taking LiNbO 3:Fe and BaTiO 3 as examples, we discuss the influence of the impurity doping level, oxidation reduction state and geometric configuration of coupling beams on the dynamic range performance. For both crystals we found that the denser the donor concentration and the higher the oxidation level, the larger the maximum possible dynamic range. For BaTiO 3 crystal the optimum angle between grating wave vector and optical axis should vary with the angle between signal and reference beams.