This　paper　mainly　analyses　Linux　Security　Module　(LSM)　and　Virtual　Filesystem　of　Linux.　Based　on　the　LSM　security　field　&　hooks,　the　method　of　marking　subject　and　object　sensitivity　label　is　designed　and　implemented　on　Linux　2.6.26.　This　system　meets　GB17859-1999＇s　requirements.　In　a　simplified　environment,　it　is　completed　that　the　system　implements　subject　and　object　sensitivity　label　according　to　security　policy　by　hooks.　©　2012　IEEE.