The foundation shear wave velocity is directly related to the soil compactness, and is adopted to evaluate the pavement subgrade compaction quality generally. The dry density and water content are considered in the existing test model of shear wave velocity while foundation stress is not considered, which causes amount of errors in soil mechanical property testing under the condition of high depth and large stress using shear wave velocity. In this paper, test apparatus of foundation stress and shear wave velocity is designed,and change features of shear wave velocity under conditions of stress spreading and stress lossing among soil particles are studied by testing shear wave velocity of clay and sandy soil with changing stress. The correlation model of foundation stress and shear wave velocity based on stress diffusion is built. The model calculating consequence and field testing data are contrastively analyzed, and the effectiveness of model is confirmed. The results show that the shear wave velocity of foundation increases with the increasing of soil stress, the velocity decreases with the increasing thickness of test soil layer in condition of identical stress, and the soil shear wave velocity is significantly affected by foundation stress.