Nowadays for measurement of refractive index of nanomaterials usually spectro-photometric and mechanical methods are used which are expensive and indirect. In this paper for measuring these parameters of zinc oxide nanomaterial with two different stabilizers, a simple optical method, Moire deflectometry, which is based on wave front analysis and geometric optics is used. In the Moire deflectometry method, the beam of light from the laser diode passes through the sample. As a result of that, a change in the sample environment is observed as deflections of the fringes. By recording of these deflections using CCD and image processing with MATLAB, the nanomaterials refractive indices can be calculated. Due to the high accuracy of this method and improved the image processing code in Matlab, the smallest changes of the refractive index in the sample can be measured. Digital Image processing is used for processing images in a way that features can be selected and being shown. The results obtained in this method show a good improvement over the other used methods.