In　order　to　solve　the　problem　of　seismic　damage　prediction　of　underground　pipeline　system,　which　lacks　investigation　data　in　planning　urban　hazardous　prevention,　rough　set　methodology　was　adopted　to　analyze　the　problem.　Firstly,　ROUSTIDA　algorithm　was　used　to　complete　missing　values　in　decision　table　of　underground　pipelines　with　incomplete　information　system.　Secondly,　an　improved　Greedy　algorithm　was　made　use　of　the　discretization　of　decision　table　and　influenced　factors　reduction　algorithm　based　on　condition　information　entropy　was　introduced　to　reduce　attributes　and　obtain　information　to　build　rule　base,　and　then　seismic　damage　prediction　of　underground　pipeline　system　can　be　analyzed　according　to　the　rule　database.　Finally,　taking　the　underground　pipelines　in　Quanzhou　as　an　example,　after　doing　lots　of　prediction　experiments　and　comparing　with　other　common　prediction　methods　such　as　the　theory　method,　the　test　result　denoted　that　the　recognition　accuracy　can　reach　90%,　and　the　method　proposed　in　the　paper　proved　to　be　effective　and　feasible.