Topological-reinforcement　and　material-strengthening　were　used　and　employed　to　improve　the　mechanical　properties　of　lattice　truss　sandwich　structures.　This　new　type　of　three-dimensional　aluminum　alloy　lattice　truss　(named　enhanced　lattice　truss)　sandwich　structure,　with　a　relative　density　ranging　from　1.7%　to　4.7%,　was　designed　and　fabricated　by　interlocking　and　vacuum-brazing　method.　The　out-of-plane　compression　and　shear　properties　of　the　enhanced　lattice　truss　sandwich　structures　(both　as-brazed　and　age-hardened　cores)　were　experimentally　and　analytically　investigated.　Good　correlations　between　analytical　predictions　and　experiment　results　were　achieved.　Experimental　results　showed　that　the　mechanical　properties　of　the　enhanced　lattice　truss　cores　were　sensitive　to　the　unit-cell　size　and　parent-alloy　properties　(i.e.　inelastic　buckling　and　tangential　modulus).　The　compressive　and　shear　characteristics　of　enhanced　lattice　truss　sandwich　structures　were　discussed　and　found　superior　to　competing　lattice　truss　structures　in　low　density　area　(0.046–0.124　g/cm3)　of　material　property　charts.　The　combination　of　topological-reinforcement　and　material-strengthening　provided　a　way　to　achieve　lightweight　sandwich　structures　with　high　specific　strengths　and　low　densities.　©　The　Author(s)　2018.