Grid　cylindrical　structure　with　infinite　variety　of　cell　shape　and　arrangement　receives　much　concern,　which　results　in　many　applications　of　these　structural　materials　in　aerospace　and　aviation　engineering.　However,　the　complexity　of　structure　will　bring　high　time-consuming　in　calculation　and　unanticipated　self-contract　in　researching　dynamic　performance.　Equations　were　used　to　get　the　equivalent　material　properties　by　theoretical　derivation.　Then　dynamic　mechanical　properties　of　both　equivalent　structure　and　grid　cylindrical　structure　were　investigated.　In　detail,　the　dynamic　deformation　and　energy　absorption　characteristics　of　the　structure　under　different　lateral　impact　velocities　were　analyzed　by　software　LS-DYNA.　The　relative　density　and　the　relative　thickness　of　the　grid　cylindrical　structure　to　equivalent　performance　effect　were　taken　into　account.　The　results　show　that　when　relative　density　and　relative　thickness　are　defined　in　certain　range,　the　equivalent　method　has　high　accuracy.　This　equivalent　method　provides　a　reference　for　the　impact　properties　of　complex　grid　cylindrical　structure　with　arrangement　periodically.　Copyright　©　(2013)　by　International　Conference　on　Fracture.