Cuprous　oxide/silver　(Cu2O/Ag)　nanocomposites　were　prepared　via　a　facile　one-step　method　and　used　to　construct　an　electrochemical　sensor　for　hydrogen　peroxide　(H2O2)　detection.　In　this　method,　AgNO3　and　Cu(NO3)(2)　were　reduced　to　Cu2O/Ag　nanocomposites　by　glucose　in　the　presence　of　hexadecyl　trimethyl　ammonium　bromide　(CTAB)　at　a　low　temperature.　The　optimum　condition　was　the　molar　ratio　of　silver　nitrate　and　copper　nitrate　of　1:10,　the　temperature　of　50　degrees　C.　Under　this　condition,　Cu2O/Ag　nanocomposites　were　obtained　with　uniformly　distributed　and　tightly　combined　Cu2O　and　Ag　nanoparticles.　The　size　of　Cu2O　particles　was　less　than　100　nm　and　that　of　Ag　particles　was　less　than　20　nm.　Electrochemical　experiments　indicate　that　the　Cu2O/Ag　nanocomposites-based　sensor　possesses　an　excellent　performance　toward　H2O2,　showing　a　linear　range　of　0.2　to　4000　M,　a　high　sensitivity　of　87.0　A　mM(-1)　cm(-2),　and　a　low　detection　limit　of　0.2　M.　The　anti-interference　capability　experiments　indicate　this　sensor　has　good　selectivity　toward　H2O2.　Additionally,　the　H2O2　recovery　tests　of　the　sensor　in　diluted　milk　solution　signify　its　potential　application　in　routine　H2O2　analysis.