To　evaluate　the　security　of　urban　water　distribution　network,　one　model　based　on　LS-SVM　was　put　forth.　On　the　basis　of　summary　and　analysis　of　influential　factors　for　urban　water　distribution　network　security,　a　set　of　indexes　used　in　the　evaluation　model　above　was　constructed.　The　nonlinear　mapping　between　the　water　distribution　networks　security　classification　and　its　conditions　were　learned　from　the　finite　samples　and　a　water　distribution　network　example　was　simulated　using　this　model.　In　addition,　the　BP　ANN　model　was　used　to　simulate　the　same　example.　Through　the　analysis　of　the　result　of　the　actual　security　level,　the　security　level　acquired　by　the　LS-SVM　model　and　BP　ANN　model,　it　may　be　found　that　the　result　acquired　by　the　LS-SVM　model　has　high　accuracy,　and　may　used　in　actual　engineering.　©　(2011)　Trans　Tech　Publications.