The anisotropic elastic parameters in granular soils have a substantial contribution in the analysis of numerous geotechnical and geological engineering problems. Accordingly, the main objective of this study is to optimize the proposed equations by Graham and Houlsby’s three parameters cross-anisotropic model using seismic waves velocities to result in more precise calculations of the parameters. To attain this objective, by assuming cross-anisotropy in granular soils, the anisotropic elastic coefficients resulting from 190 conducted laboratory tests on 11 different soil specimens relating to 7 various sandy soil types were extracted from the seismic and numerical testing results in literature. A series of simple and multiple regression analyses was then performed on the collected information to identify the probable experimental correlations among the coefficients. The required corrections were finally implemented on the original Graham and Houlsby’s model to enhance its efficiency for characterization of elastic properties in granular geomaterials.