The　hierarchical　Au-loaded　SnO2　nanoflowers　were　synthesized　using　a　new　developed　self-reductive　hydrothermal　method,　of　which　the　gas-sensing　properties　were　enhanced　significantly.　The　SnO2　hierarchical　nanoflowers　were　composed　of　well-defined　nanosheets　with　a　specific　surface　area　of　around　84　m(2)/g.　Gas　sensors　made　of　pure　and　Au-doped　SnO2　were　fabricated,　and　their　gas-sensing　properties　were　characterized.　The　1.0　at.%　Au-loaded　SnO2　sensor　prepared　by　the　new　developed　self-reductive　method　showed　much　more　excellent　selectivity　toward　ethanol　at　200　degrees　C　than　the　one　prepared　with　the　conventional　hydrothermal　method.　Its　response　to　ethanol　was　around　3　times　higher　than　that　of　the　pure　SnO2　sensor.　A　very　wide　detection　range　of　1-500　ppm　for　ethanol,　good　repeatability,　and　long-term　stability　were　also　approved.