Recent improvement in analyzing molecular orientational distribution function (ODF) at surfaces and interfaces using surface second-harmonic generation (SHG) was reviewed. The anisotropic dielectric constants of SHG-active thin layers were treated as parameters governed by ODF to be determined. The information about the nonpolar axial ordering was added when using the maximum entropy method for analyzing ODF. Importance of the imaginary part of nonlinear susceptibility elements was also pointed out. A spin-coated film of polyimide with SHG-active side chains was chosen as an example and ODFs of the rubbed surface were obtained with and without using these modified methods for comparison.