Carnosine　could　be　determined　in　the　range　between　1.0　×　10-7　and　5.5　×　10-6　M　by　differential　pulse　adsorptive　stripping　voltammetry　(DPASV)　on　a　static　mercury　electrode　after　derivatization　with　diazo-p-aminoacetophenone　(DPAAP)　at　pH　9.6-9.7.　The　detection　limit　was　6.8　×　10-8　M,　the　relative　standard　deviation　(n　=　10)　for　5.0　×　10-6　M　of　carnosine　was　1.8%.　The　coupling　reaction　and　electrochemical　reaction　mechanism　of　azo-carnosine　were　investigated　by　structure　analysis,　UV　spectroscopic,　cyclic　voltammetry,　DPASV　and　electrocapillary　at　mercury　electrodes.　A　reversible　two-electron　via　two-proton　redox　and　adsorption-controlled　process　occurred　in　four　consecutive　steps　with　an　intermediate　at　the　mercury　electrode.