Abstract: Three new PVC matrix membrane bismuth (Ⅲ) ion-selective electrodes based on triheptyldodecyl-ammonium and iodo-complex, bromo-complex, chloro-complex of bismuth (Ⅲ) ion pair were described. The electrodes show Nernstian ranges from 10^-2Mto 3×10^-6M Bi³⁺(in 0.15 M KIsolution), from 5×10^-3M to 4×10^-6M Bi³⁺(in 0.40 M KBr solution), and from 10^-2Mto 4×10^-5M Bi²⁺(in 1.5 M NaCl solution) with the slopes of 60, 40, 38 mV/pBi, respectively. The potential selectivity coefficients and other characteristics of the electrodes were reported. The selective conditions of the ligand of complex anion and the law of interference of foreign cations were discussed.