The　scientific　urban　planning　of　earthquake　resistance　and　disaster　prevention　(ERDP　planning)　is　crucial　for　backing　up　sustainable　development　of　urban　area.　Base　on　characteristics　of　urban　ERDP,　the　decision　supporting　information　system　of　the　ERDP　planning　is　developed　in　China,　the　system　adopt　the　supporting　decision　theory　and　the　advanced　information　technology　such　as　Geographical　Information　Systems　(GIS).　The　design　ideas,　system　architecture　and　function　architecture　of　the　system　are　put　forward,　and　the　schemes　of　ERDP　planning　are　formed　on　the　base　of　loss　estimation.　Using　Visual　C++　6.0　(the　Object-Oriented　Language)　to　extend　ArcObjects　by　writing　COM　components　and　develop　the　system　with　the　management　functions　and　analysis　functions.