Energy equation of two-parameter foundation - rigid plate system was established by using energy method based on the basic theory of Pasternak model. In the principle of the minimum potential energy, the relationships of foundation coefficient, foundation size, load and surface displacement of soil were obtained. The foundation coefficient expression was obtained by solving the equation system which was established with two rigid plates loading test of different size based on the above relationships and the existing determining rules of foundation coefficient. Four sandy soil-rigid plate loading tests were performed to verify the validity of this method, where the circular plates with diameter of 0.3 m and 0.6 m, and square plates with the size of 0.54 m × 0.54 m and 0.71 m ×0.71 m were used. Examples of calculating foundation settlement and considering the influence of adjacent foundation were given to illustrate the engineering significance of the two-parameter foundation model, and empirical values of two-parameter foundation coefficient for clayey soil and sandy soil were estimated for the popularization and application of the two-parameter foundation model.