The　electrochemical　behavior　of　two　new　synthesized　biacridine　derivatives,　3,　3′-disulfonyl-9,　9′-biacridine　dinitrate　(DSBADN)　and　10,　10′-dimethyl-3,　3′-disulfonyl-9,　9′-biacridine　(DMDSBA)　was　investigated　by　means　of　cyclic　voltammetry　and　linear　sweep　polarography.　In　a　HCl　solution,　the　reduction　peak　current　was　proportional　to　the　concentrations　of　DSBADN　and　DMDSBA.　The　electrochemical　study　demonstrated　that　the　reduction　peak　currents　of　DSBADN　and　DMDSBA　exhibited　adsorptive　and　diffusion-controlled　characteristics,　and　the　electrode　reaction　was　totally　irreversible.　Tryptophan　(Trp)　and　Histidine(His)　could　inhibit　the　reduction　peak　currents　of　DSBADN　and　DMDSBA　respectively,　the　extent　of　the　inhibition　was　proportional　to　the　concentrations　of　Trp　and　His.　Based　on　this　principle,　a　new　electrochemical　system　has　been　developed　for　determination　of　Trp　and　His.