In　this　paper,　a　novel　latent　heat　thermal　energy　storage　unit　filled　by　metal　foams　with　gradient　in　pore　parameters　was　proposed　to　enhance　thermal　energy　storage　performance.　Two　kinds　of　gradients,　namely　positive　and　negative　gradients,　in　porosity　and　pore　density　for　metal　foams　were　designed.　Physical　and　numerical　models　were　established　for　this　problem　to　predict　the　melting　front　evolution,　temperature　and　velocity　field　during　the　melting　process.　An　experimental　test　rig　was　built　and　measurements　on　temperature　variation　in　paraffin/metal　foam　composite　were　conducted　to　validate　the　numerical　model,　achieving　good　agreement.　The　temperature　variations　and　evolution　of　melting　front　were　explored　and　recorded.　The　numerical　results　demonstrated　that　the　positive　gradient　in　porosity　can　provide　the　better　heat　transfer　enhancement　than　the　uniform　and　negative　gradient　cases.　A　17.9%　reduction　in　full　melting　time　can　be　achieved　with　the　positive　gradient　design　of　porosity　and　simultaneously　a　better　temperature　uniformity　was　also　obtained　in　comparison　with　the　other　arrangements.　Improving　the　arrangement　of　pore　density　contributed　little　to　the　melting　process　but　the　temperature　uniformity　for　the　case　with　positive　gradient　in　pores　density　increased　by　9.1%　compared　to　the　uniform　arrangement.　An　optimization　recommended　on　a　gradient　in　porosity　of　0.89-0.95-0.98　to　further　reduce　the　full　melting　time　by　21.1%.