<p>It is now understood that changes in fault dip angle significantly influence the mechanisms of fault stick-slip. In particular, variations in dip angle affect the distribution of normal and shear stresses along the fault surface and the associated energy release during shear failure. Collectively, these factors govern fault stability and account for the variation in stick-slip behavior under different fault dip angles. These changes make the dip angle a vital factor influencing fault activation. Accordingly, there is an urgent need for further research into the mechanical properties and evolution laws of stick-slip instability movement under different dip angles. Microseismic and Acoustic Emission (AE) monitoring are crucial tools for studying the mechanical evolution of fault stick-slip, as they can capture valuable information during the fault activation process. However, the structure of the fault hinders the propagation path and intensity of AE waves from rock mass fractures, posing considerable challenges to the study of fault stick-slip mechanics using these techniques. We employed discrete element numerical simulation methods to counter these challenges to construct numerical models of stick-slip instability failure under varying dip angles. Through simulation of the mechanical behavior of particles and contacts, we investigated the characteristics of AE. We comprehensively studied the mechanical behavior and AE characteristics during the stick-slip instability motion process. This study elucidates the stress-strain evolution patterns observed during the stick-slip instability motion process, which encompass various parameters such as the number of stick-slip, initiation stress, reduction in initiation stress, and maximum stress. Furthermore, we explore the aspects of energy dissipation and AE characteristics, such as energy, magnitude, failure mechanism, and b-value. The results of this study offer a novel numerical simulation approach that can be harnessed in laboratory AE experiments and microseismic monitoring studies conducted in the field to investigate fault activation.</p>