Abstract: Shear failure is a common failure mode in geotechnical engineering. Understanding the shear failure mechanism and accurately predicting the initiation and propagation process of shear fractures is of great significance for ensuring the safety and stability of engineering structures. This paper establishes a dynamic cracking simulation method for shear-based fractures based on the scaled boundary finite element methods (SBFEM) and a non-local macro-micro damage model. It defines the concept of the positive elongation of material point pairs based on deviator strain, which can serve as a dynamic cracking criterion for predicting the propagation behaviour of shear-based fractures. The damage at a point is defined as the weighted average of material bond damage within the influence domain of that point, where material bond damage is related to the positive elongation of material point pairs based on deviator strain. An energy degradation function is introduced to establish the relationship between geometric topological damage in the structural domain and energy loss, linking topological damage with stress and strain. The energy degradation function is used to modify the stiffness matrix of SBFEM, resulting in the stiffness matrix of the subdomain in the damaged state. The dynamic governing equation of SBFEM considering structural damage is derived, and the Newmark implicit algorithm is used for time discretization of the governing equation. Finally, through three typical numerical examples, it is verified that the proposed model can effectively simulate shear failure problems, accurately capture the crack path of shear fractures, and obtain relatively accurate load-displacement curves.