Abstract: Slope stability analysis is a classic topic in soil mechanics, and many methods have been developed to calculate the safety factors of slopes. Theoretically, the finite element method can obtain the stress at any point in the computational domain, and thus it is more advantageous in stability analysis than the conventional limit equilibrium method which requires rigid body assumption. However, there still exist several shortcomings in how to use the finite element results to calculate the safety factor of a slope. In this paper, we introduce the concept of acceleration and develop a new acceleration-based approach to calculation of the safety factors of slopes. That is, among different strength reduction factors, the one that minimizes modulus of acceleration is thought to be the corresponding safety factor. This idea is more rigorous and more applicable, and examples show that it can give satisfactory results in calculating the safety factor of slopes.