Hydraulic　simulation　of　earthquake　damaged　water　distribution　system　(WDS)　is　essential　to　evaluate　seismic　service　capacity　of　WDS.　This　paper　first　deduces　outflow　models　of　the　damages　(leaks　and　breaks)　induced　by　earthquake　with　the　help　of　flow　pattern　analysis,　then　presents　comparisons　on　outflow　models　of　pipeline　damages　and　topology　models　of　damaged-pipeline　networks.　The　transformations　between　leakage　outflow　and　breakage　outflow　is　obtained　by　conversions　of　minor　head　loss　at　the　leak　and　the　frictional　head　loss　along　the　disconnected　pipelines　of　the　break.　Model　comparisons　and　application　results　shown　that　the　outflow　of　the　pipe　leakage　and　breakage　can　be　deduced　from　the　minor　head　loss　at　the　leak　and　the　frictional　head　loss　along　the　disconnected　pipe　respectively.