Abstract: Lunar regolith serves as a critical material for lunar surface construction and resource exploration missions, marking its mechanical response characteristics essential for lunar engineering applications. The van der Waals forces between lunar regolith particles are prominent under the high-vacuum lunar environment, constituting the primary mechanism responsible for the cohesion observed in lunar regolith. This distinct interparticle interaction mechanism differentiates its mechanical behavior from that of terrestrial soil under terrestrial conditions. Therefore, investigating the influence of van der Waals forces on the mechanical properties of lunar regolith is vital for understanding the mechanical behavior of lunar regolith and optimizing the lunar surface operation tools. In this study, a discrete element method (DEM)-based contact model incorporating van der Waals forces was established to simulate lunar regolith. Triaxial shear tests were conducted to analyze variations in shear strength (cohesion and internal friction angle), volumetric strain, and mechanical coordination number under different van der Waals force coefficients (D_van). The results indicate that as the D_van increases from 0 to 1 × 105, the cohesion of the lunar regolith simulant rises from 0 to 2.7 kPa, while the internal friction angle increases from 45.5° to 47.3°. A comparison of the shear strength of lunar regolith simulant under lunar and terrestrial gravity conditions reveals that it exhibits higher shear strength in the reduced lunar gravity environment. This phenomenon is primarily attributed to van der Waals forces, as they enhance interparticle bonding. The mechanical properties of the simulant were calibrated against the in-situ shear strength data for lunar regolith, yielding a cohesion of 1.1 kPa and an internal friction angle of 46.8°. Building upon this, numerical simulations of the cone penetration test (CPT) were conducted to investigate the effects of penetration velocity and cone tip angle on cone tip resistance and side frictional resistance. The results demonstrate a linear positive correlation between these parameters and penetration resistance, with the most significant disturbance to lunar regolith occurring at the initial penetration stage. This study provides an important reference for numerical simulations and analysis of the mechanical properties of lunar regolith, offering technical support for future lunar surface construction, drilling, and resource exploration.