In　this　paper,　the　boundary　element　method　(BEM)　based　on　the　elasticity　theory　is　developed　for　fracture　analysis　of　cracked　thin　structures　with　the　relative　thickness-to-length　ratio　in　the　micro-　or　nano-scales.　A　special　crack-tip　element　technique　is　employed　for　the　direct　and　accurate　calculation　of　stress　intensity　factors　(SIFs).　The　nearly　singular　integrals,　which　are　crucial　in　applying　the　BEM　for　thin-structural　problems,　are　calculated　accurately　by　using　a　nonlinear　coordinate　transformation　method.　The　present　BEM　procedure　requires　no　remeshing　procedure　regardless　of　the　thickness　of　thin　structure.　Promising　SIFs　results　with　only　a　small　number　of　boundary　elements　can　be　achieved　with　the　relative　thickness　of　the　thin　film　is　as　small　as　10−9,　which　is　sufficient　for　modeling　most　of　the　thin　bodies　as　used　in,　for　example,　smart　materials　and　micro/nano-electro-mechanical　systems.　©　2021