<p>Evaluation of cone penetration test (CPT) is a crucial component in the design of marine foundations. In this research, the penetration process was simulated by the large deformation approach with state-dependent sand model. Numerical model was validated using lab CPT test, the evolution of sand state during penetration was analysed and compared with the performance of Mohr Coulomb model. A parametric analysis was conducted to explore the dependency of cone tip resistance on sand relative density. Results show that MC model typically neglects the effect of stress evolution on the stress–strain behavior, which could lead to significant errors in cone penetration resistance. Simulating the cone penetration requires a constitutive model that considers state evolution, including stiffness, strength, and volumetric response of sand foundation. State-dependent model can accurately describe these properties, which enables the penetration process to be effectively simulated. No matter in dense or loose sands, the volumetric response near the cone tip shows a contraction trend, and the mobilized friction angle is always less than the critical friction angle. Relative density can be fitted as a logarithmic function of normalized cone resistance. The findings provide valuable reference for marine geotechnical investigations and foundation installation design.</p>