<p>The mechanical responses of jointed rock masses under pre-peak cyclic shear loading are dependent on cyclic parameters, though the underlying effects and mechanisms remain inadequately understood. This study investigates the impact of cycle amplitude (<i>A</i>), frequency (<i>f</i>), and the number of cycles (<i>N</i>) on the mechanical properties of rough joints under pre-peak cyclic shear loading. The results show that the peak shear strength under pre-peak cyclic shear loading (<i>τ</i>_p) is lower than that observed in direct shear testing (<i>τ</i>_dp) for samples with identical joint surfaces. With varying <i>f</i>, <i>τ</i>_p does not degrade monotonically but is governed by the competition between two opposing mechanisms: enhanced asperity interlocking at low levels and cumulative damage dominance at high levels. Increasing <i>A</i> accelerates the degradation of asperities but ultimately increases <i>τ</i>_p by promoting the formation of stable secondary contact surfaces via debris backfilling—a process indicated by transient acoustic emission (AE) activity. In contrast, increasing N monotonically reduces <i>τ</i>_p by exacerbating damage on the asperities. Mesoscale FEM simulations, employing the LS-DYNA full restart method, deliver direct visualization of this phenomenon. Further, analysis of hysteresis loops and the corresponding evolution of the effective plastic strain (EPS) field reveal a quantitative relationship between macroscopic stiffness reduction and the irreversible accumulation of damage at the asperity scale. This multiscale decoding of the governing mechanisms significantly advances the fundamental understanding of cyclic shear behavior in rock masses.</p>