Tin　oxide　nanostructured　arrays　with　different　morphologies　were　grown　on　stainless-steel　mesh　substrates　by　a　simple　thermal　evaporation　process.　It　was　found　that　the　SnO2　nanostructures　could　be　easily　changed　from　nanobelts　to　nanocones,　nanoneedles,　micro-rods,　ultra-long　nanowires,　and　slim　nanorods　by　controlling　the　parameters　of　growth　temperature　and　N-2/O-2　flow.　A　model　combining　vapor-liquid-solid　(VLS)-base　growth　and　vapor-solid　(VS)-tip　growth　was　proposed　to　explain　the　growth　of　SnO2　nanostructures　with　manifold　morphologies.　Field-emission　(FE)　studies　revealed　that　the　morphologies　of　these　patterned　SnO2　nanostructures　had　considerable　effects　on　the　FE　properties.　Among　these　nanostructures,　ultra-long　nanowire　arrays　had　the　lowest　turn-on　field　(similar　to　0.47　V/um)　and　the　highest　field　enhancement　factor　(similar　to　8848).　More　importantly,　the　ultra-long　nanowire　emitters　showed　excellent　FE　stability　with　fluctuations　within　2.7%.　The　enhanced　FE　properties　may　be　attributed　to　synergic　effects　arising　from　the　aligned　structures　of　the　ultra　long　nanowire　emitters,　their　smaller　areal　density　and　their　highest　aspect　ratio　(similar　to　12000).