Sn-containing　dendritic　mesoporous　silica　nanoparticles　(Sn-DMSNs)　were　successfully　prepared　by　the　in-situ　co-assembly　method.　Sn-DMSNs　preserve　original　structural　characteristics　with　three-dimensional　and　center-radial　pore　structure.　The　nanoparticle　sizes　of　Sn-DMSNs　can　be　controlled　systematically　from　170　nm　to　360　nm　depending　on　the　molar　ratio　of　NaSal/CTAB.　Sn　species　are　incorporated　into　the　matrix　of　silica　and　the　highly　dispersed　SnOx　species　are　achieved.　Sn-DMSNs　catalysts　exhibit　excellent　catalytic　performance　and　stability　in　the　propane　dehydrogenation.　The　highly　dispersed　SnOx　species　rather　than　polymeric　SnOx　or　crystalline　SnO2　species　contribute　to　the　activation　of　propane　and　formation　of　propylene.　The　molar　ratio　of　NaSal/CTAB　also　shows　an　important　role　in　the　structure　of　support　and　SnOx　species.　The　excellent　stability　of　Sn-DMSNs　catalysts　can　be　ascribed　to　the　good　ability　to　restrain　coke　formation　and　strong　interaction　between　SnOx　species　and　silica.　The　effect　of　potassium　on　Sn-DMSNs　catalyst　is　also　investigated.