This　paper　studied　a　deduction　data　generation　method　of　unexpected　atmospheric　pollution　accident　based　on　GIS,　and　conducted　the　deductive　simulation　for　accidents　based　on　the　deduction　data.　Taking　an　atmospheric　accident　as　example,　the　paper　first　generated　the　spatiotemporal　distribution　data　of　atmospheric　pollution　based　on　Gaussian　model　of　air　pollution　diffusion;　then　determined　participative　emergency　team,　supplies　and　scheduling　route　using　spatial　analysis　function　of　GIS,　and　obtained　its　space-time　distribution　data　by　the　deduction　demand　analysis　of　emergency　plan;　finally,　implemented　the　deduction　of　atmospheric　pollution　emergency　plan　using　visualization　and　temporal　data　deduction　of　ArcGIS.　The　GIS　based　deduction　data　generation　method　and　accident　deduction　method　of　atmospheric　pollution　not　only　reduced　the　difficulty　for　emergency　system　developer,　but　also　showed　outstanding　advantages　in　organization,　inquiry,　management,　visualization　and　further　deep-level　analysis　of　emergency　data.