SnO2　nanomaterials　were　synthesized　by　gas-phase　oxidation　on　different　substrates,　silicon,　Au,　Cr　and　stain　steel　respectively.　The　morphology　of　SnO2　were　observed　by　scanning　electron　microscope　(SEM),　and　the　field　emission　properties　were　characterzed.　The　results　show　that　when　current　density　reaches　to　10μA/cm2,　the　turn-on　electric　field　of　Si,　Au,　Cr　and　stain　steel　are　3.6,　2.3,　2.45,　1.7V/μm　respectively.　The　results　show　that　the　field　emission　properties　of　SnO2　on　stain　steel　substrate　takes　precedence　over　others,　and　SnO2　on　Si　substrate　is　lousiest.