Abstract: Based on the geometric relations of soil slip, a spoke method on soil slope is developed in the paper. The safety factors are obtained by the Guass quadrature method. The minimum value of safety factor is calculated by a modified JC method. The spoke method avoids the traditional division of soil slip and eliminates the calculating error resulting from oversimplification between slips. It is shown that the present method is efficient and accurate for evaluation of safety factor for soil slopes.