A　series　composite　30%　RuO2-70%SnO2/Ti　DSA　anodes　were　prepared　through　a　sol-gel　technique　by　adding　different　content　of　SnO2　seeds.　The　diffraction　peaks　of　the　SnO2　seeds　were　used　as　the　internal　calibration　indexing,　based　of　which　the　phase　structures　and　solid　solution　states　of　the　coatings　were　investigated.　The　results　show　that　the　composite　RuO2-SnO2/Ti　anodes　with　different　content　of　SnO2　seeds　could　be　prepared,in　which　SnO2seeds　do　not　grow　up　further　and　no　any　diffusion　phenomenon　appears　after　heat　treatment　at　500　°C.　It　is　observed　that　the　conventional　Ru-Sn　oxide　coating　without　seeds　is　composed　of　rutile　solid　solution　(Sn,Ru)O2　and　RuO2,　the　latter　is　from　the　segregation　of　solid　solution　during　the　heating　process.　By　Vegard　formula,　the　calculated　solid　solubility　of　Sn　in　the　coating　is　much　lower　than　the　nominal　content.