A fresh slope stability analysis method is proposed in this paper, with combining scaled boundary finite element method (SBFEM), strength reduction method (SRM) and polytree-based mesh refinement algorithm. Firstly, SBFEM and SRM (SBFEM-SRM) formulation are innovatively combined to conduct the slope stability analysis with a coarse analysis mesh. Secondly, a shear-strain-based refinement indicator is introduced to determine the elements that need to be refined, then multistage local mesh refinement can be implemented recursively on-demand via the independently developed polytree-based refinement algorithm. The accuracy and superiority of SBFEM-SRM are firstly verified using a simple slope example. The effectiveness and applicability of SBFEM-SRM combined with the polytree-based refinement algorithm is demonstrated by using two examples, including a multilayered nonhomogeneous soli slope and an actual test embankment. The advantages of different methods can be inherited in the presented method, wherein flexible polygonal elements can be solved directly, and making a strong adaptability for complex geometry equipped. Moreover, the computational burden would be alleviated efficiently without compromising accuracy, benefiting from local adaptive mesh refinement strategy. And inspired by this, the proposed method can be briefly extended to 3D slope stability analysis, wherein the application performance will be more significant.