A method to determine preferred orientation of Ni-base single crystal superalloys AM3 is presented by use of X-ray diffractometer. By rotating a sample along its surface axis during θ-scanning process to ensure the normal axis of the crystal plane to across the diffraction plane multiply, the relationship between the crystal plan and the surface is obtained. The credibility is discussed by comparing the results of calculation and experiments. The identification of single crystal superalloys and dispersion degree of crystal orientation are elucidated. It is found that this method is simple and accurate for identifying single crystal superalloys