For unsaturated soils, the soil water characteristic curve (SWCC), which represents the relationship between degree of saturation and suction, is a crucial function for determining both the soil hydraulic property and its coupled mechanical properties. However, because the tests for measuring the SWCC take a long time and the process is complicated. It is very necessary to propose a simple and practical method for predicting the SWCC of unsaturated soil. The grading curves and grading parameters of the five soils in the literature were obtained. And the fitting parameters a, n, m of the Fredlund and Xing model for five soils were obtained also. By means of the regression analysis between the grading parameters and fitting parameters of SWCC, a simple and practical method was proposed for predicting the SWCC curve based on the grading parameters. This may be helpful for engineering practice at an early stage when not much experimental data are available.