With　the　rapid　development　of　internet,　explosive　growth　of　social　network　creates　large-scale　social　network　data.　In　order　to　discover　the　potential　value　of　the　social　network　data,　many　analysis　methods　have　been　developed.　However,　using　prior　knowledge　about　the　subgraph　structure　of　a　given　network,　it　is　possible　to　identify　a　target　node　or　infer　some　useful　information.　In　this　paper,　we　mainly　consider　how　to　prevent　such　subgraph　attack,　and　propose　a　practical　method　to　battle　it.　We　use　iterative　hash　to　detect　the　isomorphic　subgraph　structures　and　try　to　greedily　match　the　anonymous　subgraphs.　Empirical　queries　on　anonymized　social　network　shows　both　the　security　and　utility　advantage　of　our　algorithm.　©2010　IEEE.