The water-soluble p-sulfonated sodium salt of calix[8]arene (III) was synthesized. The product was characterized by FT-IR, NMR and UV-Vis spectra.Then the electrochemical behaviors of p-sulfonated sodium salt of calix[8]arene in NaAc+HAc (pH = 4) buffer solution was studied. In aqueous solution, p-sulfonated calix[8]arene can be oxidized when the potential is more than 0.7 V vs SCE. It was confirmed that the reaction was a two-electron irreversible electrochemical reaction. The transfer coefficient, alpha, was measured as 0.7. At 25 degrees, the diffusion coefficient of p-sulfonated calix[8]arene was determined as 8.6 x 10(-7) cm(2) s(-1). The diffusion activation energy of p-sulfonated calix[8]arene was 18.9 kJ mol(-1) at pH = 4.