The　lightweight　and　high　efficiency　of　natural　structures　are　the　inexhaustible　sources　for　engineering　improvements.　The　goal　of　the　study　is　to　find　innovative　solutions　for　mechanical　lightweight　design　through　the　application　of　structural　bionic　approaches.　Giant　waterlily　leaf　ribs　and　cactus　stem　are　investigated　for　their　optimal　framework　and　superior　performance.　Their　structural　characteristics　are　extracted　and　used　in　the　bio-inspired　design　of　Lin　MC6000　gantry　machining　center　crossbeam.　By　mimicking　analogous　network　structure,　the　bionic　model　is　established,　which　has　better　load-carrying　capacity　than　conventional　distribution.　Finite　Element　Method　(FEM)　is　used　for　numerical　simulation.　Results　show　better　specific　stiffness　of　the　bionic　model,　which　is　increased　by　17.36%.　Finally　the　scaled　models　are　fabricated　by　precision　casting　for　static　and　dynamic　tests.　The　physical　experiments　are　compared　to　numerical　simulation.　The　results　show　that　the　maximum　static　deformation　of　the　bionic　model　is　reduced　by　about　16.22%,　with　3.31%　weight　reduction.　In　addition,　the　first　four　natural　frequencies　are　improved　obviously.　The　structural　bionic　design　is　a　valuable　reference　for　updating　conventional　mechanical　structures　with　better　performance　and　less　material　consumption.