This study examines shaped charge penetration mechanics in steel targets through integrated experiments and simulations. Controlled detonation tests on 35MnB/1045 steel plates (18–40 mm) with Cu, Pb, and Pb–Sb liners were combined with LS-DYNA’s coupled Eulerian‒Lagrangian modeling. Key findings reveal the following: (1) Penetration depth follows parabolic growth with charge density until cutting-dominated failure initiates at 200 g/m. (2) A critical 17 mm standoff maintains stable penetration, beyond which depth reduces 18.7% mm⁻¹, while thinning plates from 40 to 20 mm increases penetration by 62.3% via shear-bending failure. (3) Pb–Sb liners achieve 14.4% deeper penetration (58.0 mm) than Cu through optimized impedance properties, with dual-strand designs enhancing depth 38.8% via cumulative jet effects. Numerical validation identifies 0.5–0.8 GPa jet pressure thresholds (89%–93% energy dissipation) aligned with microstructural evidence. The results demonstrate that material selection (Pb–Sb alloys) and geometric optimization (dual-strand configurations) significantly improve demolition efficiency.