<p>The widespread distribution of aeolian sand makes understanding its shear strength characteristics under different saturation levels crucial for engineering construction. This study, based on a numerical simulation method and validated through comparison with laboratory direct shear tests, clarifies the influence of different saturation levels on the shear strength of aeolian sand particles. It also investigates the interaction mechanisms between particles in aeolian sand, considering the effects of liquid bridges. Research reveals that the shear strength of aeolian sand exhibits an “inverted S-shaped” pattern with increasing saturation level: at low saturation, the strength is dominated by the internal friction angle between particles; at medium saturation, liquid bridge forces prevail, and shear strength increases with the rise in cohesion; at high saturation, the liquid bridge effect diminishes, leading to a decrease in shear strength. The liquid bridge effect significantly influences the shear band width and force chain strength by enhancing inter-particle cohesion and stress transmission. The numerical simulation results align with the experimental findings, validating the model’s effectiveness. This study offers new insights into the mechanical behavior of aeolian sands under different saturation conditions and provides theoretical guidance for practical engineering applications involving aeolian sands.</p>