Effective　thermal　conductivity　in　open-cell　foam　with　hierarchical　pore　structure　was　estimated　using　lattice　Boltzmann　method.　A　new　structure　algorithm　was　proposed　to　reconstruct　hierarchical　pore　structure　in　open-cell　foam.　In　order　to　elucidate　the　heat　transfer　characteristics　in　hierarchical　pore　structure,　the　effect　of　structure　parameters,　namely　the　hierarchical　pore　size　ratio　(d2/d1),　the　hierarchical　pore　volume　ratio　(V2/V1),　and　temperature　on　the　effective　thermal　conductivity　was　investigated.　These　results　indicated　that　hierarchical　pore　structure　is　unfavorable　to　the　effective　thermal　conductivity　in　open-cell　foam　for　the　heat　conduction　process.　At　high　temperatures　(Tave　=　450–1650　K),　however,　the　effective　thermal　conductivity　in　hierarchical　pore　structure　is　higher　than　that　in　uniform　pore　structure　considering　heat　radiation.　Furthermore,　for　the　heat　conduction　process,　a　correlation　of　the　effective　thermal　conductivity　related　to　open-cell　foam　with　hierarchical　pore　structure　was　proposed　and　validated　by　available　experimental　data.　©　2022　Elsevier　Ltd