Soil-rock mixture is constituted by the gravel rock and the low liquid limit clay sand. Its rock content is 50%. By laboratory triaxial tests, the stress-strain, and deformation characteristics of the soil-rock mixture under four different sizes were studied. The results showed: Stress-strain curves are the hardening curve in the different confining pressure, the peak intensity of the sample decreases particularly under high confining pressure with the increase of the size ; In the different confining pressure, different soil-rock mixtures volume change increases with axial strain , and it shrinks through the shearing process; The friction and the fractal dimension of rock is similar parabolic function. Test results obtained by analysis are conducive to study more in depth of the soil-rock mixture.