To　reduce　the　vibration　of　the　plate-like　structure　under　different　boundary　conditions,　an　all-metal　damping　composite　structure　was　proposed,　and　its　damping　layer　was　entangled　metallic　wire　material　(EMWM).　A　series　of　quasi-static　compression　tests　were　carried　out　to　investigate　the　damping　property　of　the　EMWM　layer.　A　modal　test　system　was　set　up　to　evaluate　whether　the　EMWM　could　dissipate　vibration　energy.　The　evaluation　results　showed　that　the　displacement　deviation　between　the　baseplate　and　constraining　plate　of　the　structure　was　large　enough　and　the　EMWM　could　dissipate　vibration　energy　in　the　form　of　friction.　The　modal　characteristics　of　the　composite　structure　with　different　core　thicknesses　under　different　boundary　conditions　were　researched　in　this　paper　by　experimental　modal　tests.　The　outcomes　showed　that　the　damping　ratio　of　the　structure　would　be　significantly　improved　by　adding　EMWM　and　constraining　plate.　The　larger　the　thickness　of　the　core　thickness　is,　the　larger　the　damping　ratio　and　vibration　reduction　performance　of　the　composite　structure　are.　This　paper　provides　a　new　technical　way　for　the　damping　design　of　high　temperature　plate　structure.