In　allusion　to　the　low　efficiency　and　unsatisfactory　result　of　the　tradional　optimization　algorithms　in　existence　for　engineering　design　optimization,　this　paper　proposes　a　cultural　ant　colony　optimization(CACO)　algorithm　for　application　in　design　optimization　of　excavator＇s　mechanisms　to　improve　the　excavator＇s　performance　efficiently.　Through　testing　and　verifying　experiments,　it　is　concluded　that　CACO　can　discovery　knowledge　during　optimization　process　and　use　the　knowledge　to　guide　the　heuristic　searching　process,　furthermore,　it　is　an　appropriate　algorithm　for　the　optimization　of　excavator　mechanisms.　CACO　costs　less　time　and　can　get　better　quality　solution　to　improve　excavator＇s　main　porformances.　©　(2012)　Trans　Tech　Publications.