Abstract: Foundation treatment is a necessary measure in construction of high slopes on soft foundation, but at present it has few commonly acceptable guidelines on how to determine the properties of foundation soils. This paper describes a method for determining bearing capacity and deformation modulus of foundation soils using the method of analogy. Results show that such foundation is easy to meet the requirement on bearing capacity. We can demonstrate the critical slip surface will cut into the slope foundation if its soil strength is below the strength index of the slope fill. To have the same bearing capacity, foundation soils are allowed to take different combinations of strength indexes; with a fixed bearing capacity, a bigger friction angle of the soil will acquire a greater safety factor and accordingly a smaller depth of the slip surface cutting into the foundation soil. A homogeneous foundation has a value range of d/L less than 1/3 in various circumstances.