A method for determining the orientation of thin crystal layer has been proposed, namely the Raman scattering extrems technique. The intensity of Raman scattered light from the diamond structure thin layer as a function of both the normal of the thin layer and the polarization direction of incident light is derived. The orientation of the thin layer is then determined by means of four extrema of this function. The results obtained by this method, for silicon wafers are compared with that dettermined by the X-ray method.