<p>This study systematically explores the layer-spacing-dependent high-harmonic generation (HHG) characteristics in AA-stacking bilayer MoS₂ under variable laser wavelengths through numerical solutions of the extended multiband semiconductor Bloch equations (SBEs). The computational results reveal a universal inverse correlation between harmonic conversion efficiency and excitation wavelength, with emission intensity exhibiting progressive attenuation as the laser wavelength increases. Crucially, spectral modifications emerge upon interlayer spacing expansion: Distinct interference minima manifest in the harmonic spectra, whose depth amplifies monotonically with increasing interlayer separation. Microscopically, this is attributed to the pronounced suppression of specific transition dipole moments and the consequent modification of quantum phase accumulation between electron trajectories. This phenomenon originates from destructive quantum interference between harmonics generated independently within each monolayer, which is a consequence of phase mismatch accumulation during interlayer electron transport. Specifically, expanded layer spacing reduces wavefunction overlap between the two MoS₂ layers, enhancing the relative phase difference of recombination pathways and thereby intensifying coherent subtraction effects. These findings establish interlayer spacing as a critical degree of freedom for tailoring quantum interference patterns in van der Waals heterostructures, while simultaneously highlighting the competing roles of wavelength-dependent tunneling dynamics and interlayer decoupling in solid-state HHG processes.</p>