The　composite　of　gold　nanoparticles-graphene　oxide　(AuNPs-GO)　was　prepared　and　characterized　by　transmission　electron　microscope　(TEM)　and　ultraviolet-visible(UV-vis)　spectrophotometry,　respectively.　The　composite　was　modified　on　the　surface　of　a　glassy　carbon　electrode　(GCE).　The　mercapto-modified　and　guanine-rich　DNA　strand　(T30695)　was　self-assembled　on　to　gold　nanoparticles　on　the　surface　of　the　electrode　via　Au-S　bond.　T30695　could　combine　with　lead　ions　(Pb2+)　to　form　a　stable　parallel　G-quadruplex.　The　G-quadruplex　further　combined　with　hemin　to　form　DNAzyme　with　peroxidase　activity.　On　the　basis　of　this,　DNAzyme　electrochemical　sensor　Pb2+　detection　was　prepared.　The　DNAzyme　could　catalyze　the　oxidation　reaction　of　hydrogen　peroxidetowardshydroquinone　(HQ)　to　achieve　the　amplification　of　electrochemical　signal　and　highly　sensitive　detection　of　Pb2+.　Under　the　optimum　conditions,　the　peak　current　of　square-wave　voltammetry　(SWV)　was　linearly　dependent　on　the　logarithm　of　Pb2+　concentration　ranging　from　5.　0　x10(-9)　mol/L　to　1.　0　x10(-6)　mol/L　with　a　detection　limit　of　1.　0　x10(-9)　mol/L　(S/N　=　3).　The　recovery　of　Pb2+　in　real　water　sample　was　96%　-105%.　The　sensor　possessed　good　reproducibility,　stability　and　selectivity　to　Pb2+.