We systematically study the plasticity and melting behavior in shock loading, as well as their dependence on porosity (ϕ) and specific surface area (γ) for nanoporous copper (NPC), by conducting large-scale non-equilibrium molecular dynamics simulations. During shock compression, the plasticity (i.e., dislocation slips) is dominant at lower impact velocities, while melting is governing at higher impact velocities. With increasing ϕ, both the plasticity and melting undergo the transitions from “heterogeneity” to “homogeneity” along the tr...