In　this　study,　a　kind　of　nanoporous　gold　electrode　(NPG)　prepared　with　repetitive　square-wave　oxidation　reduction　cycle　(SWORC)　was　reported.　The　active　surface　area　of　the　proposed　NPG　electrode　was　9.9　times　larger　than　that　of　a　bare　flat　one　characterized　by　cyclic　voltammetry　(CV).　An　electrochemical　DNA　biosensor　based　on　NPG　electrode　was　fabricated　for　detection　of　promyelocytic　leukemia/retinoic　acid　receptor　α　(PML/RARα)　fusion　gene　in　acute　promyelocytic　leukemia　(APL)　by　using　Methylene　Blue　(MB)　as　an　electroactive　indicator.　Differential　pulse　voltammetry　(DPV)　was　employed　to　monitor　the　hybridization　reaction　on　the　probe　modified　electrode.　The　decrease　of　the　peak　current　of　MB　was　observed　upon　hybridization　of　the　probe　with　target　DNA.　The　results　indicated　that　the　peak　current　was　linear　with　the　concentration　of　complementary　strand　in　the　range　of　60　pM　to　220　pM　with　a　detection　limit　of　6.7.　pM.　This　new　biosensor　exhibited　excellent　sensitivity　and　selectivity　and　had　been　used　for　an　assay　of　PCR　real　sample　with　a　satisfactory　result.　©　2011　Elsevier　B.V.