Lattice　sandwich　beams　are　often　subjected　to　vibrations　when　they　are　used.　The　aim　of　this　study　was　to　explore　the　vibration　characteristics　of　the　octet-truss　lattice　core　sandwich　beam　by　translating　discrete　octet-truss　core　to　the　continuous　homogenization　material.　The　natural　frequencies　of　which　are　obtained　by　theoretical　calculation　and　numerical　simulation.　The　theoretical　solutions　are　in　good　agreement　with　the　numerical　results.　It　demonstrates　that　the　theoretical　approach　is　effective　to　compute　the　natural　frequency.　Furthermore,　the　influences　of　truss　member　radius　and　thin　sheets　ply　on　the　natural　frequencies　are　also　discussed.　The　outcomes　indicate　that　the　octet-truss　lattice　core　sandwich　beam＇s　natural　frequencies　are　controlled　via　selecting　the　appropriate　truss　member　radius　and　the　face　sheets　thickness.　©　2021　Institute　of　Physics　Publishing.　All　rights　reserved.